Microbial growth has been shown, in many instances to be dependent upon the uptake of metabolites from the culture medium into the cell (1, 2). The formation of the essential “uptake systems” appears not only to be under genetic control but, in some cases, to be an inducible capacity of the organism (1,2). This communication is concerned with the uptake of metabolites by two amino acid auxotrop...

About 2 years ago the author reported that the activity of purified preparations of succinic dehydrogenase is enhanced by phosphate buffer (2). This enhancement was dependent upon the phosphate concentration and appeared to be relatively specific for phosphate, since other buffers, such as Tris,l imidazole, histidine, glycylglycine, and arsenate did not induce it (2, 3). Arsenate, in fact, inte...

In a mixture containing γ-glutamyl donor (donor) and γ-glutamyl acceptor (acceptor), the glutaminase of Pseudomonas nitroreducens IFO 12694 simultaneously catalyzed a γ-glutamyl transfer reaction and hydrolysis of the donor. The variation of the activities responding to the concentration of glutathione and glycylglycine indicated that the enzyme might be classified in a group of glutaminases th...

The catalytic decomposition of hydrogen peroxide by Cu(II) complexes with polymers bearing L-alanine (PAla) and glycylglycine (PGlygly) in their side chain was studied in alkaline aqueous media. The reactions were of pseudo-first order with respect to [H(2)O(2)] and [L-Cu(II)] (L stands for PAla or PGlygly) and the reaction rate was increased with pH increase. The energies of activation for the...

Two types of peptidases are present in tissues, one of which catalyzes the hydrolysis of the saturated, RCHCONHCHR’COOH,l the other that of the unsaturated, RCHCONHC(=CHR’)COOH~RCHCON=C(CH~R’)COOH, peptide bonds (cf. (1)). These are designated, respectively, peptidases and dehydropeptidases. We have reported the rates of hydrolysis of variously constituted dehydropeptides in extracts of rat tis...

Response surface methodology (RSM) offers an empirical approach to the study of clinical enzyme assays. Variables such as pH, which are difficult to characterize by using theoretical enzyme kinetics, are easily included in RSM formulations. In this investigation, we studied with RSM the change in the measured activity of gamma-glutamy-transferase (EC 2.3.2.2) as a function of changes in concent...