A rapid and accurate spectrophotometric assay has been developed for the determination of blood werum levels of gentamicin and related antibiotics. The assay uses a purified enzyme from Escherichia coli JR88/C600 that acetylates gentamicin with the production of coenzyme A, linked to a chemical reaction with a sulfhydryl reagent to produce stoichiometric amounts of a sensitive chromophore, moni...

The glutathione-insulin transhydrogenase from beef liver haa been found to promote the reductive cleavage of the disulfide bonds of insulin by simple sulfhydryl compounds such as glutathione (2). The properties of this enzyme are of interest not only because of its probable involvement in the biological regulation of the level of insulin but also because, at present, it is the only isolated mam...

Williamson, W. T. (North Carolina State of the University of North Carolina, Raleigh), S. B. Tove, and M. L. Speck. Extracellular proteinase of Streptococcus lactis. J. Bacteriol. 87:49-53. 1964.-Streptococcus lactis was shown to produce an extracellular proteolytic enzyme(s). A 120-fold purification of the proteinase was obtained from the cell-free culture medium by ammonium sulfate fractionat...

The catalytic activity of rabbit liver fructose diphosphatase is enhanced more than fourfold by treatment with coenzyme A or acyl carrier protein. Other sulfhydryl compounds, such as glutathione or cysteine, are without effect. Activation is reversed by reduced glutathione or cysteine, indicating that the enzyme and activator are linked by disulfide bridges. The activated enzyme derivative can ...

A methyl methanesulfonate sensitive mutant of Bacillus subtilis appears to lack the enzyme DNA polymerase I. The absence of polymerase I permits the detection of a second DNA polymerizing enzyme in the mutant. This second polymerase is inhibitable by sulfhydryl antagonists, and shows maximal activity on double-stranded DNA substrates with many single strand breaks. Poly[d(A-T)] is less efficien...

Amidase (EC 3.5.1.4) was purified to homogeneity from Rhodococcus rhodochrous M8 using isopropanol fractionation and exchange chromatography on Mono Q. The isolated amidase consists of four identical subunits with molecular weight 42+/-2 kD. The activity of the enzyme is maximal at 55-60 degrees C and within the pH range 5-8. The amidase from R. rhodochrous M8 is highly sensitive to such sulfhy...

A dipeptidase was purified to homogeneity from a crude cell extract of Streptococcus cremoris Wg2 by DEAE-Sephacel column chromatography followed by preparative disc gel electrophoresis. Sodium dodecyl sulfate-polyacrylamide gel electrophoresis of the purified enzyme showed a single protein band with a molecular weight of 49,000. The dipeptidase is capable of hydrolyzing a range of dipeptides, ...

In previous papers from these laboratories (1, 2) methods for the purification of the collagenase of Clostridiurm histolyticum were presented, and a calcium ion requirement for the binding of the enzyme to collagen and for the overall enzymatic action was reported. In the present, communication an additional method of purification, which makes possible the large-scale preparation of the enzyme,...

The present communication describes the elucidation of the sequence of amino acid residues around the single half-cysteinyl residue (Liu, Neumann, Elliott, Moore, and Stein (1)) of the proteinase derived from the zymogen produced by Group A hemolytic streptococci (Elliott (2)). This -SH group is essential for the proteolytic activity of the reduced enzyme; therefore, as a working hypothesis, th...

S-Adenosylmethionine decarboxylase (EC 4.1.1.50) has been purified 500-fold in 30% yield from the extract of etiolated corn seedlings (cv. Golden Crossbantam Bell). This preparation had a molecular weight of approximately 25,000. The K(m) value was 5 micromolar for S-adenosylmethionine. Methylglyoxal bis(guanylhydrazone), hydroxylamine, and sulfhydryl reagents (such as p-hydroxymercuriphenylsul...