Salvatore Foti - Academia.edu (original) (raw)
Papers by Salvatore Foti
The Journal of Peptide Research, 2009
We report here the total synthesis of the a-amylase inhibitor (AAI), a 32-residue-long peptide wi... more We report here the total synthesis of the a-amylase inhibitor (AAI), a 32-residue-long peptide with three disulfide bridges, isolated from amaranth seeds (Chagolla-Lopez. A., Blanco-Labra, A., Patthy, A., Sanchez, R. & Pongor S . (1994) . I .
XII International Citrus Congress - International Society of Citriculture, 2015
Tetrahedron, 1986
ABSTRACT
Cereal Chemistry, 2002
Cereal Chem. 79(6):768-770 The molecular weights of nine C hordein proteins, including all of the... more Cereal Chem. 79(6):768-770 The molecular weights of nine C hordein proteins, including all of the major components identified by SDS-PAGE have been determined by MALDI-MS. Most were in the range 43,561 to 46,857, with a single component of M r 57,606. These are higher than the masses previously
Biophysical Journal, 2016
U. S. Naval Radiological Defense Iaborafory, Sun Francisco 24, Calif. b A new volumetric method f... more U. S. Naval Radiological Defense Iaborafory, Sun Francisco 24, Calif. b A new volumetric method for determining molybdenum in a high chloride medium is described. After passage through a Jones reductor the reduced molybdenum is caught under a receiver solution of sodium molybdate whose pH is so adjusted that an equivalent amount of molybdenum blue is formed. The molybdenum blue is then titrated to a colorless equivalence point with standard ceric sulfate solution. The formation of molybdenum blue serves two purposes: The oxidation-reduction reaction between molybdenum(lll) and molybdenum(V1) forms an intermediate oxidation state that is stable against air oxidation and the intermediate oxidation state, molybdenum blue, serves as its own indicator in the titration. The results are comparable to those obtained by the use of the permanganate method in sulfuric acid. HE PERNAPI'GANATE titration of a T molybdenum-sulfuric acid solution, reduced to molybdenum(II1) by passage through a Jones reductor and caught under excess ferric sulfate, is accurate (5) except in the presence of an appreciable amount of chloride ion despite the addition of Zimmermann-Reinhardt solution. I n this case a ceric titration of a cooled solution of molybdenum(V) in 2N hydrochloric acid that has been reduced by passage through a silver reductor maintained a t 60" to 80" C. is employed. Ferrous o-phenanthroline complex is used as indicator (2). Hiskey, Springer, and Meloche have shown that the normality of the hydrochloric acid must be closely controlled around 2N to prevent the reduction from falling short or passing beyond the pentapositive state.
Oncotarget, Jan 8, 2016
Voltage-Dependent Anion selective Channels (VDAC) are pore-forming mitochondrial outer membrane p... more Voltage-Dependent Anion selective Channels (VDAC) are pore-forming mitochondrial outer membrane proteins. In mammals VDAC3, the least characterized isoform, presents a set of cysteines predicted to be exposed toward the intermembrane space. We find that cysteines in VDAC3 can stay in different oxidation states. This was preliminary observed when, in our experimental conditions, completely lacking any reducing agent, VDAC3 presented a pattern of slightly different electrophoretic mobilities. This observation holds true both for rat liver mitochondrial VDAC3 and for recombinant and refolded human VDAC3. Mass spectroscopy revealed that cysteines 2 and 8 can form a disulfide bridge in native VDAC3. Single or combined site-directed mutagenesis of cysteines 2, 8 and 122 showed that the protein mobility in SDS-PAGE is influenced by the presence of cysteine and by the redox status. In addition, cysteines 2, 8 and 122 are involved in the stability control of the pore as shown by electrophysi...
Molecular BioSystems, 2013
Mitochondria carry maternally inherited genetic material, called the mitochondrial genome (mtDNA)... more Mitochondria carry maternally inherited genetic material, called the mitochondrial genome (mtDNA), which can be defined as the 25th human chromosome. The chromosome-centric Human Proteome Project (c-HPP) has initially focused its activities addressing the characterization and quantification of the nuclear encoded proteins. Following the last International HUPO Congress in Boston (September 2012) it was clear that however small the mitochondrial chromosome is, it plays an important role in many biological and physiopathological functions. Mutations in the mtDNA have been shown to be associated with dozens of unexplained disorders and the information contained in the mtDNA should be of major relevance to the understanding of many human diseases. Within this paper we describe the Italian initiative of the Human Proteome Project dedicated to mitochondria as part of both programs: chromosome-centric (c-HPP) and Biology/Disease (B/D-HPP). The mt-HPP has finally shifted the attention of the HUPO community outside the nuclear chromosomes with the general purpose to highlight the mitochondrial processes influencing the human health. Following this vision and considering the large interest and evidence collected on the non-Mendelian heredity of Homo sapiens associated with mt-chromosome and with the microbial commensal ecosystem constituting our organism we may speculate that this program will represent an initial step toward other HPP initiatives focusing on human phenotypic heredity.
Organic Mass Spectrometry, 1985
![Research paper thumbnail of Structural characterization of 1,3,4-thiadiazolo [3,2-a][1,3,5] triazines by electron impact mass spectrometry](https://attachments.academia-assets.com/43153396/thumbnails/1.jpg)
](Organic Mass Spectrometry, Jun 1, 1989
The electron-impact-induced fragmentation of eleven 1,3,4thiadiazolo[3,2-a][ 1,3,qtiazines was in... more The electron-impact-induced fragmentation of eleven 1,3,4thiadiazolo[3,2-a][ 1,3,qtiazines was investigated with the aid of exact mass measurements, B/E and B2/E linked scans, and deuterated compounds. The dominating breakdown process in the electron impact mass spectra of 2-substituted 6-phenyl-l,3,4thiadiamlo[3,2-~]-[1,3,5]triazine-5,7diones (1-5) is a retro-Diels-Alder reaction. This process gives rise to the base peak, whereas the molecular ions are of very low intensity. In the mass spectra of 2-substituted 7-rnethylthio-l,3,4thiadiazolo-[3,2~][1,3,5]triadne-5soes (611) in which this fragmentation cannot occur because of the two conjugated double bonds in the triazine ring, the molecular ions are very intense. The mass spectral data permits an unequivocal structure assignment to these compounds, which are otherwise difficult to characterize. Scheme 2 1,3,4-THIADIAZOLO[3,2-a] [ 1,3,5]TRIAZINES
Eur Mass Spectrom, 2004
In less then a decade, applications of matrix-assisted laser desorption/ionisation (MALDI) and el... more In less then a decade, applications of matrix-assisted laser desorption/ionisation (MALDI) and electrospray ionisation (ESI) mass spectrometry to the investigation of prolamins have rapidly evolved from measurements of the molecular mass of isolated proteins to a proteomic approach attempting to characterise the complete protein pattern in the seed. Mass spectrometry is currently making significant contributions to the understanding of the composition and structure of the gluten proteins and, in turn, to the elucidation of structure-function relationships. Results obtained using mass spectrometry, including determination of the molecular masses of prolamins, direct verification of gene-derived sequences, determination of the number of cysteine residues and localisation of disulphide bonds, investigation of the gluten toxicity for celiac patients, qualitative and quantitative determination of gliadins in food and determination of the protein pattern and its modification during seed maturation by proteomic approaches, are summarised here, to illustrate current trends and individuate possible future perspectives.
Rapid Communications in Mass Spectrometry, 2003
Structural studies of the high molecular weight (HMW) glutenin subunits 1Dy10 and 1Dy12 of bread ... more Structural studies of the high molecular weight (HMW) glutenin subunits 1Dy10 and 1Dy12 of bread wheat were conducted using matrix-assisted laser desorption/ionisation time-of-flight mass spectrometry (MALDI-TOFMS) and reversed-phase high-performance liquid chromatography/electrospray ionisation mass spectrometry (RP-HPLC/ESI-MS). For both proteins, MALDI-TOFMS analysis showed that the isolated fractions contained a second component with a mass about 500-540 Da lower than the major component. The testing and correction of the gene-derived amino acid sequences of both proteins were performed by direct MALDI-TOFMS analysis of their tryptic peptide mixture and analysis of the digests was performed by recording several MALDI mass spectra of the mixture at low, medium and high mass ranges, optimising the matrix and the acquisition parameters for each mass range. Complementary data were obtained by RP-HPLC/ESI-MS analysis of the tryptic digest. This resulted in the coverage of the whole protein sequences except for two short fragments (T1 and T8), which are identical in the two homologous subunits, and for an additional dipeptide (T14) in subunit 1Dy12, which were not detected. It also demonstrated that, in contrast to the gene-derived data, the sequence of subunit 1Dy12 does not include the dipeptide Gly-Gln between residues Gln(454) and Pro(455), and that the lower mass components present in both fractions correspond to the same sequences lacking short peptides that are probably lost from the protein N- or C-termini. Finally, the results obtained provide evidence for the lack of a substantial level of glycosylation or other post-translational modifications of the two subunits, and demonstrate that mass spectrometric mapping is the most useful method presently available for the direct verification of the gene-derived sequences of HMW glutenin subunits and similar proteins.
Rapid Commun Mass Spectrom, 2004
... Francesco Galliano 1 ,; Rosaria Saletti 1 ,; Vincenzo Cunsolo 1 ,; Salvatore Foti 1,* ,; Dona... more ... Francesco Galliano 1 ,; Rosaria Saletti 1 ,; Vincenzo Cunsolo 1 ,; Salvatore Foti 1,* ,; Donata Marletta 2 ,; Salvatore Bordonaro 2 ,; Giuseppe D'Urso 2. Article first published online: 30 JUL 2004. DOI: 10.1002/rcm.1575. ... Garro G, Mauriello R, Ferranti P, Pizzano R. Lait 1993; 73: 553 ...
Eur Mass Spectrom, 2001
The structural characterisation of a synthetic peptide reproducing the sequence 1-30 of Par j 1.0... more The structural characterisation of a synthetic peptide reproducing the sequence 1-30 of Par j 1.0101, a major allergenic protein present in the pollen of Parietaria judaica, by combined use of chemical and enzymatic cleavage, reversed-phase highperformance liquid chromatography and electrospray ionisation mass spectrometry (ESI-MS), is described. Direct ESI-MS of the synthetic peptide after reaction with methyl iodide showed that the product is a mixture of two peptides: one form in which two out of the four cysteine residues present in the sequence are oxidised and a minor amount of another form in which all the cysteines are fully reduced. It was ascertained, using the combined procedure indicated above and without prior separation of the two species, that the disulphide bond in the partially oxidised form is located between cysteines 29 and 30. These results show the usefulness of this approach for characterising synthetic peptides containing multiple cysteine residues in the sequence.
J Mass Spectrometry, 2009
Four co-eluting components, with experimentally measured Mr of 23 658, 23 786, 24 278 and 24 406 ... more Four co-eluting components, with experimentally measured Mr of 23 658, 23 786, 24 278 and 24 406 Da, were detected by reversed-phase high-performance liquid chromatography (RP-HPLC) and matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS) analysis in the dephosphorylated casein fraction of a milk sample collected at middle lactation stage from an individual donkey belonging to the Ragusano breed. By coupling RP-HPLC, two-dimensional polyacrylamide gel electrophoresis (2D-PAGE), enzymatic digestions, MALDI-TOF MS and capillary RP-HPLC/nano-electrospray ionization tandem mass spectrometry (nESI-MS/MS) analyses, the four components were identified as donkey's αs1-CNs and their sequences completely characterized, using the known mare's αs1-CN (GenBank Acc. No. AAK83668; Mr 23750.7 Da) as reference. The proteins with Mr of 23 786 and 23 658 Da differ in the presence of a glutamine residue at position 83 in the full-length component and present the amino acid substitutions Q8H and H115Y with respect to the mare's αs1-CN. The other two components with Mr 24 406 and 24 278 Da, which also differ in the presence of a glutamine residue at position 88 in the full-length component, show the insertion of the pentapeptide HTPRE between Leu33 and the Glu34. The two αs1-CNs bearing the pentapeptide insertion were named variants A (202 amino acids; Mr 24 406) and A1 (201 amino acids; Mr 24 278), whereas the two αs1-CNs without the pentapeptide were named variants B (197 amino acids; Mr 23 786) and B1 (196 amino acids; Mr 23 658). Copyright © 2009 John Wiley & Sons, Ltd.
Journal of Polymer Science: Polymer Chemistry Edition, 1977
The synthesis of a series of polyamides and copolyamides containing a-truxillic and adipic units ... more The synthesis of a series of polyamides and copolyamides containing a-truxillic and adipic units in the chain is reported. The thermal degradation of these polymers was investigated by direct pyrolysis in the ion source of a mass spectrometer. Thermal degradation reactions were followed directly by this method by detecting the thermal-and electron-impact-induced fragments. The results obtained show a good correlation between the intensity of mass peaks characteristic of truxillic and adipic moieties and the composition of the copolyamides, as ascertained by elemental analysis. This is an important result since it shows the potential of the direct pyrolysis method in the analysis of copolymers. Relevant information on the relative thermal stabilities of the polymers investigated has been also obtained.
Journal of Polymer Science: Polymer Chemistry Edition, 1981
The primary fragmentation mechanisms in the thermal decomposition of polyurethanes were studied i... more The primary fragmentation mechanisms in the thermal decomposition of polyurethanes were studied in detail by direct pyrolysis into the mass spectrometer. The remarkable difference in the thermal stability of the two totally aromatic polyurethanes I and I1 ) reflects their different decomposition pathways. In fact, polymer I undergoes a depolycondensation process that yields diisocyanate and dialcohol as primary thermal fragments. The thermal decomposition of polymer I1 proceeds instead via the formation of a cyclic compound that has been isolated and characterized. In contrast, open-chain fragments are generated in the thermal decomposition of the partially aliphatic polymer 111.
Angewandte Makromolekulare Chemie
ABSTRACT
Angewandte Makromolekulare Chemie
ABSTRACT
The Journal of Peptide Research, 2009
We report here the total synthesis of the a-amylase inhibitor (AAI), a 32-residue-long peptide wi... more We report here the total synthesis of the a-amylase inhibitor (AAI), a 32-residue-long peptide with three disulfide bridges, isolated from amaranth seeds (Chagolla-Lopez. A., Blanco-Labra, A., Patthy, A., Sanchez, R. & Pongor S . (1994) . I .
XII International Citrus Congress - International Society of Citriculture, 2015
Tetrahedron, 1986
ABSTRACT
Cereal Chemistry, 2002
Cereal Chem. 79(6):768-770 The molecular weights of nine C hordein proteins, including all of the... more Cereal Chem. 79(6):768-770 The molecular weights of nine C hordein proteins, including all of the major components identified by SDS-PAGE have been determined by MALDI-MS. Most were in the range 43,561 to 46,857, with a single component of M r 57,606. These are higher than the masses previously
Biophysical Journal, 2016
U. S. Naval Radiological Defense Iaborafory, Sun Francisco 24, Calif. b A new volumetric method f... more U. S. Naval Radiological Defense Iaborafory, Sun Francisco 24, Calif. b A new volumetric method for determining molybdenum in a high chloride medium is described. After passage through a Jones reductor the reduced molybdenum is caught under a receiver solution of sodium molybdate whose pH is so adjusted that an equivalent amount of molybdenum blue is formed. The molybdenum blue is then titrated to a colorless equivalence point with standard ceric sulfate solution. The formation of molybdenum blue serves two purposes: The oxidation-reduction reaction between molybdenum(lll) and molybdenum(V1) forms an intermediate oxidation state that is stable against air oxidation and the intermediate oxidation state, molybdenum blue, serves as its own indicator in the titration. The results are comparable to those obtained by the use of the permanganate method in sulfuric acid. HE PERNAPI'GANATE titration of a T molybdenum-sulfuric acid solution, reduced to molybdenum(II1) by passage through a Jones reductor and caught under excess ferric sulfate, is accurate (5) except in the presence of an appreciable amount of chloride ion despite the addition of Zimmermann-Reinhardt solution. I n this case a ceric titration of a cooled solution of molybdenum(V) in 2N hydrochloric acid that has been reduced by passage through a silver reductor maintained a t 60" to 80" C. is employed. Ferrous o-phenanthroline complex is used as indicator (2). Hiskey, Springer, and Meloche have shown that the normality of the hydrochloric acid must be closely controlled around 2N to prevent the reduction from falling short or passing beyond the pentapositive state.
Oncotarget, Jan 8, 2016
Voltage-Dependent Anion selective Channels (VDAC) are pore-forming mitochondrial outer membrane p... more Voltage-Dependent Anion selective Channels (VDAC) are pore-forming mitochondrial outer membrane proteins. In mammals VDAC3, the least characterized isoform, presents a set of cysteines predicted to be exposed toward the intermembrane space. We find that cysteines in VDAC3 can stay in different oxidation states. This was preliminary observed when, in our experimental conditions, completely lacking any reducing agent, VDAC3 presented a pattern of slightly different electrophoretic mobilities. This observation holds true both for rat liver mitochondrial VDAC3 and for recombinant and refolded human VDAC3. Mass spectroscopy revealed that cysteines 2 and 8 can form a disulfide bridge in native VDAC3. Single or combined site-directed mutagenesis of cysteines 2, 8 and 122 showed that the protein mobility in SDS-PAGE is influenced by the presence of cysteine and by the redox status. In addition, cysteines 2, 8 and 122 are involved in the stability control of the pore as shown by electrophysi...
Molecular BioSystems, 2013
Mitochondria carry maternally inherited genetic material, called the mitochondrial genome (mtDNA)... more Mitochondria carry maternally inherited genetic material, called the mitochondrial genome (mtDNA), which can be defined as the 25th human chromosome. The chromosome-centric Human Proteome Project (c-HPP) has initially focused its activities addressing the characterization and quantification of the nuclear encoded proteins. Following the last International HUPO Congress in Boston (September 2012) it was clear that however small the mitochondrial chromosome is, it plays an important role in many biological and physiopathological functions. Mutations in the mtDNA have been shown to be associated with dozens of unexplained disorders and the information contained in the mtDNA should be of major relevance to the understanding of many human diseases. Within this paper we describe the Italian initiative of the Human Proteome Project dedicated to mitochondria as part of both programs: chromosome-centric (c-HPP) and Biology/Disease (B/D-HPP). The mt-HPP has finally shifted the attention of the HUPO community outside the nuclear chromosomes with the general purpose to highlight the mitochondrial processes influencing the human health. Following this vision and considering the large interest and evidence collected on the non-Mendelian heredity of Homo sapiens associated with mt-chromosome and with the microbial commensal ecosystem constituting our organism we may speculate that this program will represent an initial step toward other HPP initiatives focusing on human phenotypic heredity.
Organic Mass Spectrometry, 1985
Organic Mass Spectrometry, Jun 1, 1989
The electron-impact-induced fragmentation of eleven 1,3,4thiadiazolo[3,2-a][ 1,3,qtiazines was in... more The electron-impact-induced fragmentation of eleven 1,3,4thiadiazolo[3,2-a][ 1,3,qtiazines was investigated with the aid of exact mass measurements, B/E and B2/E linked scans, and deuterated compounds. The dominating breakdown process in the electron impact mass spectra of 2-substituted 6-phenyl-l,3,4thiadiamlo[3,2-~]-[1,3,5]triazine-5,7diones (1-5) is a retro-Diels-Alder reaction. This process gives rise to the base peak, whereas the molecular ions are of very low intensity. In the mass spectra of 2-substituted 7-rnethylthio-l,3,4thiadiazolo-[3,2~][1,3,5]triadne-5soes (611) in which this fragmentation cannot occur because of the two conjugated double bonds in the triazine ring, the molecular ions are very intense. The mass spectral data permits an unequivocal structure assignment to these compounds, which are otherwise difficult to characterize. Scheme 2 1,3,4-THIADIAZOLO[3,2-a] [ 1,3,5]TRIAZINES
Eur Mass Spectrom, 2004
In less then a decade, applications of matrix-assisted laser desorption/ionisation (MALDI) and el... more In less then a decade, applications of matrix-assisted laser desorption/ionisation (MALDI) and electrospray ionisation (ESI) mass spectrometry to the investigation of prolamins have rapidly evolved from measurements of the molecular mass of isolated proteins to a proteomic approach attempting to characterise the complete protein pattern in the seed. Mass spectrometry is currently making significant contributions to the understanding of the composition and structure of the gluten proteins and, in turn, to the elucidation of structure-function relationships. Results obtained using mass spectrometry, including determination of the molecular masses of prolamins, direct verification of gene-derived sequences, determination of the number of cysteine residues and localisation of disulphide bonds, investigation of the gluten toxicity for celiac patients, qualitative and quantitative determination of gliadins in food and determination of the protein pattern and its modification during seed maturation by proteomic approaches, are summarised here, to illustrate current trends and individuate possible future perspectives.
Rapid Communications in Mass Spectrometry, 2003
Structural studies of the high molecular weight (HMW) glutenin subunits 1Dy10 and 1Dy12 of bread ... more Structural studies of the high molecular weight (HMW) glutenin subunits 1Dy10 and 1Dy12 of bread wheat were conducted using matrix-assisted laser desorption/ionisation time-of-flight mass spectrometry (MALDI-TOFMS) and reversed-phase high-performance liquid chromatography/electrospray ionisation mass spectrometry (RP-HPLC/ESI-MS). For both proteins, MALDI-TOFMS analysis showed that the isolated fractions contained a second component with a mass about 500-540 Da lower than the major component. The testing and correction of the gene-derived amino acid sequences of both proteins were performed by direct MALDI-TOFMS analysis of their tryptic peptide mixture and analysis of the digests was performed by recording several MALDI mass spectra of the mixture at low, medium and high mass ranges, optimising the matrix and the acquisition parameters for each mass range. Complementary data were obtained by RP-HPLC/ESI-MS analysis of the tryptic digest. This resulted in the coverage of the whole protein sequences except for two short fragments (T1 and T8), which are identical in the two homologous subunits, and for an additional dipeptide (T14) in subunit 1Dy12, which were not detected. It also demonstrated that, in contrast to the gene-derived data, the sequence of subunit 1Dy12 does not include the dipeptide Gly-Gln between residues Gln(454) and Pro(455), and that the lower mass components present in both fractions correspond to the same sequences lacking short peptides that are probably lost from the protein N- or C-termini. Finally, the results obtained provide evidence for the lack of a substantial level of glycosylation or other post-translational modifications of the two subunits, and demonstrate that mass spectrometric mapping is the most useful method presently available for the direct verification of the gene-derived sequences of HMW glutenin subunits and similar proteins.
Rapid Commun Mass Spectrom, 2004
... Francesco Galliano 1 ,; Rosaria Saletti 1 ,; Vincenzo Cunsolo 1 ,; Salvatore Foti 1,* ,; Dona... more ... Francesco Galliano 1 ,; Rosaria Saletti 1 ,; Vincenzo Cunsolo 1 ,; Salvatore Foti 1,* ,; Donata Marletta 2 ,; Salvatore Bordonaro 2 ,; Giuseppe D'Urso 2. Article first published online: 30 JUL 2004. DOI: 10.1002/rcm.1575. ... Garro G, Mauriello R, Ferranti P, Pizzano R. Lait 1993; 73: 553 ...
Eur Mass Spectrom, 2001
The structural characterisation of a synthetic peptide reproducing the sequence 1-30 of Par j 1.0... more The structural characterisation of a synthetic peptide reproducing the sequence 1-30 of Par j 1.0101, a major allergenic protein present in the pollen of Parietaria judaica, by combined use of chemical and enzymatic cleavage, reversed-phase highperformance liquid chromatography and electrospray ionisation mass spectrometry (ESI-MS), is described. Direct ESI-MS of the synthetic peptide after reaction with methyl iodide showed that the product is a mixture of two peptides: one form in which two out of the four cysteine residues present in the sequence are oxidised and a minor amount of another form in which all the cysteines are fully reduced. It was ascertained, using the combined procedure indicated above and without prior separation of the two species, that the disulphide bond in the partially oxidised form is located between cysteines 29 and 30. These results show the usefulness of this approach for characterising synthetic peptides containing multiple cysteine residues in the sequence.
J Mass Spectrometry, 2009
Four co-eluting components, with experimentally measured Mr of 23 658, 23 786, 24 278 and 24 406 ... more Four co-eluting components, with experimentally measured Mr of 23 658, 23 786, 24 278 and 24 406 Da, were detected by reversed-phase high-performance liquid chromatography (RP-HPLC) and matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS) analysis in the dephosphorylated casein fraction of a milk sample collected at middle lactation stage from an individual donkey belonging to the Ragusano breed. By coupling RP-HPLC, two-dimensional polyacrylamide gel electrophoresis (2D-PAGE), enzymatic digestions, MALDI-TOF MS and capillary RP-HPLC/nano-electrospray ionization tandem mass spectrometry (nESI-MS/MS) analyses, the four components were identified as donkey's αs1-CNs and their sequences completely characterized, using the known mare's αs1-CN (GenBank Acc. No. AAK83668; Mr 23750.7 Da) as reference. The proteins with Mr of 23 786 and 23 658 Da differ in the presence of a glutamine residue at position 83 in the full-length component and present the amino acid substitutions Q8H and H115Y with respect to the mare's αs1-CN. The other two components with Mr 24 406 and 24 278 Da, which also differ in the presence of a glutamine residue at position 88 in the full-length component, show the insertion of the pentapeptide HTPRE between Leu33 and the Glu34. The two αs1-CNs bearing the pentapeptide insertion were named variants A (202 amino acids; Mr 24 406) and A1 (201 amino acids; Mr 24 278), whereas the two αs1-CNs without the pentapeptide were named variants B (197 amino acids; Mr 23 786) and B1 (196 amino acids; Mr 23 658). Copyright © 2009 John Wiley & Sons, Ltd.
Journal of Polymer Science: Polymer Chemistry Edition, 1977
The synthesis of a series of polyamides and copolyamides containing a-truxillic and adipic units ... more The synthesis of a series of polyamides and copolyamides containing a-truxillic and adipic units in the chain is reported. The thermal degradation of these polymers was investigated by direct pyrolysis in the ion source of a mass spectrometer. Thermal degradation reactions were followed directly by this method by detecting the thermal-and electron-impact-induced fragments. The results obtained show a good correlation between the intensity of mass peaks characteristic of truxillic and adipic moieties and the composition of the copolyamides, as ascertained by elemental analysis. This is an important result since it shows the potential of the direct pyrolysis method in the analysis of copolymers. Relevant information on the relative thermal stabilities of the polymers investigated has been also obtained.
Journal of Polymer Science: Polymer Chemistry Edition, 1981
The primary fragmentation mechanisms in the thermal decomposition of polyurethanes were studied i... more The primary fragmentation mechanisms in the thermal decomposition of polyurethanes were studied in detail by direct pyrolysis into the mass spectrometer. The remarkable difference in the thermal stability of the two totally aromatic polyurethanes I and I1 ) reflects their different decomposition pathways. In fact, polymer I undergoes a depolycondensation process that yields diisocyanate and dialcohol as primary thermal fragments. The thermal decomposition of polymer I1 proceeds instead via the formation of a cyclic compound that has been isolated and characterized. In contrast, open-chain fragments are generated in the thermal decomposition of the partially aliphatic polymer 111.
Angewandte Makromolekulare Chemie
ABSTRACT
Angewandte Makromolekulare Chemie
ABSTRACT