Giovanni Maurizi - Academia.edu (original) (raw)

Papers by Giovanni Maurizi

European journal of biochemistry, Jun 28, 2008

The mammalian enzyme pantetheinase, which hydrolyzes pantetheine to pantothenic acid and cysteami... more The mammalian enzyme pantetheinase, which hydrolyzes pantetheine to pantothenic acid and cysteamine, is inhibited by many thiol reagents and activated by thiols. Two thiol groups of different reactivity and accessibility are involved in the catalytic process [Ricci, G., Nardini, M., Chiaraluce, R., Duprk, S. & Cavallini, D. (1986) Biochim. Biophys. Actu 870, 82-91]. The inhibition kinetics by some natural and synthetic disulfides [pantethine, cystamine, 5,5'-dithiobis(2-nitrobenzoic acid), 4,4'-dithiodipyridine and oxidized mercaptoethanol] has been studied by two experimental approaches, either by monitoring activity after incubation of the enzyme with the inhibitor or by determining the progress curves in the presence of substrate and inhibitor. Data reported here indicate that pantetheinase reacts irreversibly with various disulfides in a time-dependent manner with the formation of a mixed disulfide apparently preceeded by a conformational change, giving a modified E* form with new kinetic parameters. This modified form may be further competitively inhibited by disulfides interacting with the enzyme at the active site.

Journal of Protein Chemistry, Apr 1, 1992

Denaturation of human seminal transferrin (HSmT) compared with human serum transferrin (HSrT) was... more Denaturation of human seminal transferrin (HSmT) compared with human serum transferrin (HSrT) was followed to check structural differences between these two proteins. Second derivative UV spectroscopy indicated that treatment with 6 M guanidine hydrochloride (Gnd.HCI) induced greater structural changes in HSrT than in HSmT and, in particular; (i) the exposure value of tyrosinyl residues was almost 2.5-fold higher in native HSmT than in native HSrT; and (ii) a much more pronounced movement of tryptophanyl residues toward a higher polar environment could be noticed in HSrT after incubation with denaturating agent. Fluorescence measurements showed that: (i) a shift of the maximum emission wavelength of HSmT occurred (maximum emission was centered at 333 nm instead of 323 nm as for HSrT; excitation= 280 nm) ; (ii) the intrinsic tryptophan fluorescence intensity of HSmT increased after 36 hr in the range of 1.5-4.0 M of denaturant, whereas an opposite behavior was found for HSrT in the range 0.0 2.0 M; and (iii) the wavelength maximum of fluorescence emission changed in a biphasic manner for HSrT and, conversely, under the same experimental conditions, HSmT gave a linear and parallel increase of fluorescence emission after 1 and 36 hr. We carl conclude that this different behavior of HSmT with respect to HSrT might be due mainly to the fact that both the number and the exposure of tyrosinyl and tryptophanyl residues are different. Lately, these effects are discussed in relationship with the fact that HSmT contains less than half disulphide bridges than HSrT.

International Journal of Pharmaceutics, Aug 1, 1991

Ampicillin has been entrapped in phospholipid vesicles by reverse-phase evaporation technique. Th... more Ampicillin has been entrapped in phospholipid vesicles by reverse-phase evaporation technique. The relationship between lipid composition and the encapsulation efficiency or the release of ampicillin-loaded liposomes was studied in vitro using a derivative sp~ctrophotomet~ assay. The encapsufation degree was closely dependent on the lipid mixture used in liposome preparation: in particular, phosphatidylcholine (DPPC) vesicles containing cholesterol tCHOt or ii~~polysaccharide (LPS) had a lower entrapment efficiency than liposomes prepared with DPPC alone. whereas the presence of cardioiipin (CL) conferred an opposite trend. From the release kinetics it appeared that vesicles leaked the carried drug by a hiphasic feature both dialyzing against buffer or in bulk solution. These observations indicate that for the in vivo use of ampicillin-loaded liposomes as chemotherapeutic agents one must pay attention to the lipid composition of the vesicle, in order to modulate the dose-response effect,

International Journal of Immunopathology and Pharmacology, 1994

PubMed, Mar 1, 2001

The role of endogenous IL-1beta in regulating spontaneous and Fas-triggered apoptosis of human PM... more The role of endogenous IL-1beta in regulating spontaneous and Fas-triggered apoptosis of human PMN has been studied in relation to the activity of the IL-1beta-generating enzyme ICE (caspase-1), an enzyme also involved in the mechanism of cell death. Upon in vitro culture, PMN undergo spontaneous apoptosis and express increasing levels of IL-1beta, caspase-1- and caspase-3-like enzymes. Endogenous IL-1beta protects PMN from apoptosis, since inhibition of either IL-1beta or caspase-1 activity can accelerate PMN apoptotic death. Thus, in spontaneous PMN apoptosis caspase-1 essentially plays an anti-apoptotic role by inducing maturation of protective IL-1beta, whereas other molecules are responsible of driving apoptosis. Upon Fas triggering, PMN apoptosis is greatly accelerated, in correlation with increased caspase activity, whereas IL-1beta production is not augmented. Inhibition of IL-1beta activity can increase Fas-induced apoptosis, whereas caspase-1 inhibitors are without significant effect. It is hypothesized that in Fas-induced PMN apoptosis caspase-1 has a double role: it can protect from apoptosis through generation of protective IL-1beta, as in spontaneous apoptosis, and it can also exert pro-apoptotic activity which counterbalances the protective effect and allows accelerated apoptosis.

Biochimica Et Biophysica Acta - General Subjects, Mar 1, 1992

Pharmaceutica acta Helvetiae, 1988

European cytokine network, 1997

Human neuroblastoma cells SK-N-SH express significant numbers of IL-1R type I on their surface, a... more Human neuroblastoma cells SK-N-SH express significant numbers of IL-1R type I on their surface, as detected by saturation binding and RT-PCR, and are responsive to IL-1beta activation by producing inflammatory cytokines IL-6 and IL-8. IL-1beta can also have an indirect effect on nervous cell functions, since it is able to modulate the stimulus-induced increase of intracellular Ca++ levels, one of the first steps of the cell activation mechanism. In fact, on SK-N-SH neuroblastoma cells, IL-1beta can inhibit the Ca++ increase induced by stimulation of acetylcholine receptors with carbachol. In parallel to IL-1beta, the neurotrophic factor CNTF also shows an inhibitory effect on carbachol-stimulated Ca++ increase in CNTFRalpha-expressing SK-N-SH cells. However, when simultaneously present, the two cytokines cross-inhibit, thus allowing full cell activation in response to the cholinoceptor agonist. The inhibitory effect of CNTF on IL-1beta activities on nervous cells was confirmed in th...

Il Farmaco; edizione pratica, 1988

Journal of immunology (Baltimore, Md. : 1950), Jan 15, 1997

A series of mutants of human IL-1 receptor antagonist (IL-1ra) has been designed by comparison of... more A series of mutants of human IL-1 receptor antagonist (IL-1ra) has been designed by comparison of IL-1ra and IL-1beta structures in order to increase receptor antagonist capacity. Upon in vitro and in vivo assay of IL-1 antagonism, the IL-1ra mutants DoB 0039 (N91-->R), DoB 0040 (T109-->A) and DoB 0041 (N91/T109-->R/A) could inhibit IL-1beta effects more efficiently than wild-type IL-1ra, with DoB 0041 being the most active. Analysis of the receptor-binding capacity of the IL-1ra mutants showed that all three mutants could inhibit binding of IL-1alpha or IL-1beta to IL-1RI-bearing cells more efficiently than wild-type IL-1ra. Conversely, binding of IL-1beta to IL-1RII-bearing cells could be inhibited by DoB 0041 much less efficiently than by wild-type IL-1ra. It is known that the two types of IL-1 receptors (IL-1RI and IL-1RII) play different roles in the regulation of IL-1 activity, with IL-1RI being solely responsible for cell triggering upon IL-1 binding, whereas IL-1RII...

Microbial Cell Factories - MICROB CELL FACT, 2006

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European cytokine network

The apoptosis-defective lpr (fas) mutation in MRL mice causes the early onset of a lupus-like aut... more The apoptosis-defective lpr (fas) mutation in MRL mice causes the early onset of a lupus-like autoimmune disease with concomitant inflammation. In order to analyse the consequences of the impaired Fas-dependent apoptosis on inflammation, the susceptibility to apoptosis of polymorphonuclear leukocytes (PMN), obtained from MRL lpr/lpr mice, has been studied. Peritoneal PMN from lpr/lpr and control (+/+) mice were recruited with a mild inflammatory stimulus. The number of cells collected from the peritoneal cavity of young lpr/lpr mice was comparable to that obtained from age-matched control mice, indicating that PMN homeostasis is maintained regardless of the loss-of-function Fas mutation. Recruited neutrophils were exposed in culture to apoptosis-inducing stimuli. Treatment with agonist anti-Fas antibody increased apoptosis of +/+ PMN, but did not affect lpr/lpr PMN which do not express Fas on their surface. However, lpr/lpr PMN could undergo both spontaneous and stimulus-induced apo...

Cellular and molecular biology, 1991

In this paper we report some structural features of human seminal transferrin (HSmT) in compariso... more In this paper we report some structural features of human seminal transferrin (HSmT) in comparison with the homologous protein purified from human serum (HSrT). In particular, the sequence of the first 13 N-terminal amino acids of HSmT shows 12/13 of identity with the first 13 N-terminal amino acids of HSrT, the ninth residue of the former protein being not definitely determined. Moreover, HSrT and HSmT analysed under the same conditions, by means of reversed phase HPLC, thiol groups determination and second derivative spectroscopy, show a different content of amino acids. In particular, HSmT exhibits mainly: i) a lower Asx/Glx ratio; ii) a reduction of about 50% in Cys residues; iii) a decrease of Tyr and Trp residues. Eventually oligosaccharide parallel analyses of HSmT and HSrT show the same glycosidic bond and almost the same sugar content (around 5.5% w/w); conversely, HSmT lacks of sialic acid residues and probably it contains fucose. These results, taken all together, could b...

Zygote, 1993

SummaryIn amphibian eggs the formation of a capsular chamber is one of the most striking events o... more SummaryIn amphibian eggs the formation of a capsular chamber is one of the most striking events occurring either upon oviposition or after fertilisation. In the egg of the anuranDiscoglossus pictusa capsular chamber forms following fertilisation or activation; the egg with its vitelline envelope rotates in this chamber according to gravity. Previous work showed that the chamber is the product of plug dissolution. The plug is a lens-shaped jelly coat, typical ofDiscoglossus, covering only part of the animal hemisphere. Its dissolution is caused by material released from the egg about 15 min after fertilisation through exocytosis of at least two types of vacuoles. Liquefaction of the plug correlates with the reduction of disulphide bonds present in the jelly matrix. In this study we investigated the nature of the substances released from the egg and some changes occurring in the plug during liquefaction. SDS-PAGE showed that the proteic profile of the plug changes dramatically after f...

The International journal of developmental biology, 1992

Discoglossus pictus is one of the few anurans with an egg where a capsular chamber forms as a con... more Discoglossus pictus is one of the few anurans with an egg where a capsular chamber forms as a consequence of fertilization; the egg with its vitelline envelope rotates in this chamber according to gravity. We investigated the formation of the capsular chamber through various experimental cytochemical and ultrastructural approaches, and found that it is the product of plug liquefaction. The plug is a lens-shaped jelly coat typical of Discoglossus, and covering only part of the egg animal half. About 15 min after fertilization, granular material coming from the egg enters the plug, which gradually dissolves and, once liquefied, reorganizes itself around the entire egg, thus forming the chamber. This process goes through stages of rearrangement of the 25-A- and 250-A-thick filaments which constitute the plug matrix. The material entering the plug derives from the exocytosis of two vacuole types, with electron transparent and granular PAS-positive contents. Liquefaction of the plug corr...

Systemes et compositions destines a l'apport de composes therapeutiques a un animal, ces syst... more Systemes et compositions destines a l'apport de composes therapeutiques a un animal, ces systemes consistant a administrer a l'animal une bacterie recombinee, laquelle code la proteine therapeutique.

European cytokine network, 2001

Journal of Protein Chemistry, 1992

Protein Expression and Purification, 1997

volved in many immune and inflammatory processes, including pathological events of acute and chro... more volved in many immune and inflammatory processes, including pathological events of acute and chronic inHuman interleukin 1 receptor antagonist (IL-1ra) and IL-1ra mutants were constitutively expressed in recom-flammation (1,2). IL-1ra is the antagonist member of binant Bacillus subtilis in endocellular and active form. the family: it exerts its activity by competing with IL-In order to optimize the purification of the recombinant 1 for binding to its receptors (3-5). The inhibitory acproteins, a new method has been developed. After bactivity of IL-1ra on the IL-1 effects makes it a candidate terial growth in fermenter, release of recombinant profor therapeutic use in a number of pathologies in which tein was achieved by starvation-induced sporulation. IL-1 activity is involved.