Abstract
Conditions for the accurate measure of glutamic dehydrogenase (GDH) from Cephalosporium acremonium were determined. Km values for α-ketoglutarate and ammonium ion were 7 and 15 mM, respectively. The half-saturation for reduced nicotinamide adenine dinucleotide phosphate was 5 μM. Reduced nicotinamide adenine dinucleotide did not serve as a cofactor for the enzyme. The specific activity of GDH was measured in six mutants of C. acremonium which varied in their ability to synthesize cephalosporin C. The mutants represented two separately derived lines, A and B. The four mutants in line B were characterized by a derepression of the GDH upon entry into stationary phase. The two mutants in line A were characterized by repressed levels of GDH during the same period. Both lines exhibited high GDH activity early in their fermentations, but activity decreased during the period of active cell growth. Cytochrome c concentrations followed the same pattern as total soluble intracellular protein. Line A mutants were low in cephalosporin C productivity and line B encompassed low, intermediate, and high productivity mutants. The relative frequency of yield improvements in line A and B indicate that the altered regulation pattern for GDH in line B may have removed a nitrogen limitation for cephalosporin C synthesis.
Full text
PDF





Selected References
These references are in PubMed. This may not be the complete list of references from this article.
- Benz F., Liersch M., Nüesch J., Treichler H. J. Methionine metabolism and cephalosporin C synthesis in Cephalosporium acremonium. D-amino acid oxidase. Eur J Biochem. 1971 May 11;20(1):81–88. doi: 10.1111/j.1432-1033.1971.tb01365.x. [DOI] [PubMed] [Google Scholar]
- Caltrider P. G., Niss H. F. Role of methionine in cephalosporin synthesis. Appl Microbiol. 1966 Sep;14(5):746–753. doi: 10.1128/am.14.5.746-753.1966. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Dennen D. W., Carver D. D. Sulfatase regulation and antibiotic synthesis in Cephalosporium acremonium. Can J Microbiol. 1969 Feb;15(2):175–181. doi: 10.1139/m69-029. [DOI] [PubMed] [Google Scholar]
- LOWRY O. H., ROSEBROUGH N. J., FARR A. L., RANDALL R. J. Protein measurement with the Folin phenol reagent. J Biol Chem. 1951 Nov;193(1):265–275. [PubMed] [Google Scholar]
- Lemke P. A., Nash C. H. Mutations that affect antibiotic synthesis by Cephalosporium acremonium. Can J Microbiol. 1972 Feb;18(2):255–259. doi: 10.1139/m72-038. [DOI] [PubMed] [Google Scholar]
- LéJohn H. B., Stevenson R. M., Meuser R. Multivalent regulation of glutamic dehydrogenases from fungi. Effects of adenylates, guanylates, and acyl coenzyme A derivatives. J Biol Chem. 1970 Nov 10;245(21):5569–5576. [PubMed] [Google Scholar]
- Nash C. H., Huber F. M. Antibiotic synthesis and morphological differentiation of Cephalosporium acremonium. Appl Microbiol. 1971 Jul;22(1):6–10. doi: 10.1128/am.22.1.6-10.1971. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Pateman J. A. Regulation of synthesis of glutamate dehydrogenase and glutamine synthetase in micro-organisms. Biochem J. 1969 Dec;115(4):769–775. doi: 10.1042/bj1150769. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Queener S. W., Capone J. J., Radue A. B., Nagarajan R. Synthesis of deactoxycephalosporin C by a mutant of Cephalosporium acremonium. Antimicrob Agents Chemother. 1974 Sep;6(3):334–337. doi: 10.1128/aac.6.3.334. [DOI] [PMC free article] [PubMed] [Google Scholar]
