Results 121 to 130 of about 1,344 (153)

Genetic recombination in the cephamycin producer,Streptomyces clavuligerus

European Journal of Applied Microbiology, 1977
In order to study the mechanism of cephamycin production by streptomycetes and to use genetic recombination in strain development, we undertook genetic studies inStreptomyces lipmanii andS. clavuligerus. S. lipmanii crosses gave 0.005–1.3% “prototroph-like” colonies, but all segregated back to parental genotypes. Crosses ofS.
Y. Aharonowitz, A. L. Demain
openaire   +1 more source

Alanine dehydrogenase of the ?-lactam antibiotic producer Streptomyces clavuligerus

Archives of Microbiology, 1980
L-Alanine dehydrogenase was found in extracts of the antibiotic producer Streptomyces clavuligerus. The enzyme was induced by ammonia, and the level of induction was dependent on the extracellular concentraction. L-Alanine was the only amino acid able to induce alanine dehydrogenase.
Y, Aharonowitz, C G, Friedrich
openaire   +2 more sources

Pathways and Regulation of Ammonium Assimilation in Streptomyces clavuligerus

Microbiology, 1986
Summary: Glutamine synthetase, glutamate synthase and alanine dehydrogenase activities were detected in crude extracts of Streptomyces clavuligerus. Glutamate dehydrogenase and alanine: 2-oxoglutarate aminotransferase could not be found. Glutamate synthase levels were independent of the nitrogen source in the culture medium.
A. F. BRANA, N. PAIVA, A. L. DEMAIN
openaire   +1 more source

Regulation of extracellular protease production in Streptomyces clavuligerus

Applied Microbiology and Biotechnology, 1990
The production of extracellular protease by Streptomyces clavuligerus was strongly influenced by the nature of the nitrogen source. Production took place in batch cultures during growth at low or intermediate growth rates, but was delayed to the post-exponential phase in media supporting high growth rates.
Victoria Bascar�n, Carlos Hardisson, Alfredo F. Bra�a   +2 more
openaire   +1 more source

Metabolic Engineering of Cephalosporin Biosynthesis in Streptomyces clavuligerus

Annals of the New York Academy of Sciences, 1994
The biosynthesis of beta-lactams is one of the most thoroughly studied antibiotic pathways. The availability of the characteristics and the time profiles of activities of enzymes involved in the biosynthesis allows one to critically evaluate the potential rate-limiting steps in its production.
A, Khetan, L H, Malmberg, D H, Sherman, W S, Hu   +3 more
openaire   +2 more sources

Precursor and Cofactor as a Check Valve for Cephamycin Biosynthesis in Streptomyces clavuligerus

Biotechnology Progress, 1999
The biosynthesis of secondary metabolites is closely linked to primary metabolism via the supply of precursors, cofactors, and cellular energy. The availability of these precursors and cofactors can potentially be rate-limiting for secondary metabolism.
A, Khetan, L H, Malmberg, Y S, Kyung, D H, Sherman, W S, Hu   +4 more
openaire   +2 more sources

Purification and properties of isopenicillin N epimerase from Streptomyces clavuligerus

Biochimica et Biophysica Acta (BBA) - Protein Structure and Molecular Enzymology, 1989
Isopenicillin N epimerase, which catalyzes conversion of isopenicillin N to penicillin N, has been purified to electrophoretic homogeneity from the cell-free extract of Streptomyces clavuligerus by a procedure involving ammonium sulfate fractionation and chromatographies with DE-52, DEAE Affi-gel blue, Sephadex G-200, calcium phosphate-cellulose, and ...
S, Usui, C A, Yu
openaire   +2 more sources

Nitrogen nutrition and regulation of cephalosporin production in Streptomyces clavuligerus

Canadian Journal of Microbiology, 1979
When used as sole nitrogen source, certain amino acids (e.g., proline, asparagine) supported both growth and sporulation by Streptomyces clavuligerus streaked onto solid defined medium. Ammonium supported growth but suppressed sporulation. Amino nitrogen was best for cephalosporin production in liquid defined medium, although urea was almost as useful.
Y, Aharonowitz, A L, Demain
openaire   +2 more sources

Kinetic Mechanism of the β-Lactam Synthetase of Streptomyces clavuligerus

Biochemistry, 2000
Streptomyces clavuligerus beta-lactam synthetase (beta-LS) was recently demonstrated to catalyze an early step in clavulanic acid biosynthesis, the ATP/Mg(2+)-dependent intramolecular closure of the beta-amino acid N(2)-(carboxyethyl)-L-arginine (CEA) to the monocyclic beta-lactam deoxyguanidinoproclavaminic acid (DGPC).
B O, Bachmann, C A, Townsend
openaire   +2 more sources

Purification of isopenicillin N synthetase from Streptomyces clavuligerus

Canadian Journal of Microbiology, 1986
Isopenicillin N synthetase was purified from Streptomyces clavuligerus by sequential salt precipitation, ion-exchange and gel-filtration chromatography using both conventional open column and high-performance liquid chromatographic techniques. Material from the final purification step had a specific activity of 204.1 × 10−3 units/mg of protein which ...
S E, Jensen, B K, Leskiw, L C, Vining, Y, Aharonowitz, D W, Westlake, S, Wolfe   +5 more
openaire   +2 more sources