Characterization of subspecies from a fungal fatty acid synthetase (original) (raw)

Subunit Composition of Fatty Acid Synthetase from Fungi

Biochemical Society Transactions, 1978

the presence of the first product inhibitor, unlike the case of a simple Ping Pong Bi Bi mechanism (Cleland, 1970). From plots of rj,, and QB against formaldehyde concentration, values were obtained of 0.64 M for KiJ(k-6/k+b) and 0.53 M for K i (= k+Jk+).

Evidence that the multifunctional polypeptides of vertebrate and fungal fatty acid synthases have arisen by independent gene fusion events

FEBS letters, 1983

The enoyl reductase (NADPH binding site) of rabbit mammary fatty acid synthase has been radioactively labelled using pyridoxal phosphate and sodium [3H]borohydride. Using this method we have been able to add this site to the four sites whose location has already been mapped within the multifunctional polypeptide chain of the protein. The results show that the enoyl reductase lies between the 3-oxoacylsynthase and the acyl carrier. This confirms that the active sites occur in a different order on the single multifunctional polypeptide of vertebrate fatty acid synthase and the two multifunctional polypeptides of fungal fatty acid synthase, and suggests that these two systems have arisen by independent gene fusion events.

Aspergillus has distinct fatty acid synthases for primary and secondary metabolism

Proceedings of the National Academy of Sciences, 1996

Aspergillus nidulans contains two functionally distinct fatty acid synthases (FASs): one required for primary fatty acid metabolism (FAS) and the other required for secondary metabolism (sFAS). FAS mutants require long-chain fatty acids for growth, whereas sFAS mutants grow normally but cannot synthesize sterigmatocystin (ST), a carcinogenic secondary metabolite structurally and biosynthetically related to aflatoxin. sFAS mutants regain the ability to synthesize ST when provided with hexanoic acid, supporting the model that the ST polyketide synthase uses this short-chain fatty acid as a starter unit. The characterization of both the polyketide synthase and FAS may provide novel means for modifying secondary metabolites.

Distribution of yeast fatty acid synthetase subunits: three-dimensional model of the enzyme

Proceedings of the National Academy of Sciences, 1978

Rabbit and goat antibodies against the isolated a and (3 subunits of yeast fatty acid synthetase were raised and characterized. The purified IgG fractions were studied as to their capability to precipitate their antigens and the holoenzyme and to inhibit the partial reactions involved in overall fatty acyl-CoA synthesis. The specificity of the antibodies was investigated by immunodiffusion and by immunotitration. Native enzyme was crosslinked with each of the antibodies, and dimeric and oligomeric groups of IgG-crosslinked fatty acid synthetase molecules were isolated by sucrose density gradient

Biochemical Characterization for Lipid Synthesis in Aspergillus niger

Baghdad Science Journal, 2016

A niger, a fungus which doesn't have high ability to production lipid, this fungus has been select to investigate the non oleaginicity. In this search, there are explorations about: i) growth profile ii) enzymes profile iii) isoforms. Growth profile shows that this fungus doesn't have ability to accumulate lipid more than 6% while bio mass are around 10g/l in spite of the presence of glucose in the media till the end of cultivation time and excision of nitrogen within 24 hrs. In enzyme study, we investigate all lipogenic enzymes Malic enzyme (ME), Fatty acid synthase (FAS), ATP: Citrate lays (ACL), NAD + isocitrate dehydrogenase (NAD + ICDH), Glucose-6phosphate (G6PD), and 6-phosphogluconate dehydrogenase (6PGD), all these enzymes show, activities till the end of cultivation time including ACL which is regarded the key enzyme to differentiate between the two species oleaginous and non oleaginous. So, there is no main reason to non oleaginicity for this fungus. A further experiment has been done using Polyacrylamide gel electrophoresis to identify ME isoforms. The result of Polyacrylamide gel electrophoresis shows multi isoforms (A, B, C, D & E), with low intensity of isoform E, the isoforms that may involve in lipid synthesis. We have now studied the biochemistry of A.niger grown under conditions designed to promote lipid accumulation and can now advance a coherent hypothesis to explain why A niger could not accumulate lipid more than 6%. So the absence of isoforme E is the main reason for non oleaginicity in A niger.

Presence of two polypeptide chains comprising fatty acid synthetase

Proceedings of the National Academy of Sciences, 1975

Highly purified fatty acid synthetases of chicken and rat livers have molecular weights of 500,000 and dissociate in solutions of low ionic strength into subunits of molecular weight 250,000 with loss of synthetase activity. The subunits can be reassociated in phosphate buffer with full restoration of the activity. In the presence of sodium dodecyl sulfate or guanifine-HCl, the synthetases dissociate into polypeptide chains of molecular weight 220,000 as determined by sodium dodecyl sulfate-gel electrophoresis and sedimentation equilibrium. The polypeptide contains the 4-phosphopantetheine group and the [14C]acetyl and [4C]malonyl groups if the synthetases were prelabeled with [14C]acetyl-CoA and [14C]malonyl-CoA. Similar results were obtained with the synthetase from yeast, except the subunit has a molecular weight of 200,000. These observations indicate that the multi-catalytic activities of the synthetases and the acyl carrier protein are associated only with the two polypeptide ...