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Query: UNIPROT:P00790 (PGA)
 2,475 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

To understand the mechanism by which gamma-polyglutamic acid (gamma-PGA) in the sticky material of natto was synthesized, we purified the gamma-glutamyltranspeptidase (gamma-GTP) (EC 2.3.2.2) from the culture broth of Bacillus subtilis (natto) to homogeneity. gamma-GTP was composed of two subunits with molecular weight of 45,000 and 22,000. The N-terminal amino acid sequence of light subunit was homologous with that of gamma-GTP from Escherichia coli. The optimum pH and temperature of activity were 8.5 and 60 degrees C. The enzyme was inactivated by incubation for 15 min at pH 8.0 and 55 degrees C, but little loss of the activity was detected at 40 degrees C. gamma-GTP used glutamine as a gamma-glutamyl donor and acceptor for gamma-PGA synthesis. Dipeptides were better gamma-glutamyl acceptors than free amino acids.
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PMID:Purification and properties of gamma-glutamyltranspeptidase from Bacillus subtilis (natto). 137 Oct 53

Two isozymes of gamma-glutamyltranspeptidase, GGT-A and GGT-B, were purified to electrophoretic homogeneity from a culture broth of Bacillus subtilis TAM-4, which produces poly(gamma-glutamic acid) (PGA) de novo. GGT-A was composed of three subunits with molecular weights of 23,000 (I), 39,000 (II), and 40,000 (III). GGT-B was composed of two subunits with molecular weight of 22,000 (I) and 39,000 (II). The N-terminal amino acid sequences of GGT-A subunit I and GGT-B subunit I were very similar. GGT-A subunit II and GGT-B subunit II had an identical N-terminal amino acid sequence. That of GGT-A subunit III showed no similarity to the other subunits. Both GGTs had similar enzymatic properties (optimum pH and temperature: pH 8.8 and 55 degrees C) but showed a significantly different thermal stability at 55 degrees C. Both GGT-A and -B used D-gamma-glutamyl-p-nitroanilide as well as the L-isomer as the gamma-glutamyl donor and used various amino acids and peptides as the acceptor. It was also found that the PGA produced by the strain was hydrolyzed to glutamic acid by its own GGTs.
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PMID:Purification and properties of two isozymes of gamma-glutamyltranspeptidase from Bacillus subtilis TAM-4. 936 11