Agricultural and Biological Chemistry · 1981 · 62 citations · 0 references
Life SciencesBiochemistryMicrobiologyBiocatalysisEnzymologyProtein BiochemistryEnzyme CharacterizationEnzyme InhibitionEnzyme IsolationEnzyme PurificationEnzyme StabilityProtein PurificationBacterial ProteasesChromatographic Enzyme PurificationDipeptidyl PeptidasesElectrophoresisEnzyme Recovery From Crude ExtractsFractionationProteolytic ActivityStreptococcus Species
A dipeptidase capable of hydrolyzing L-Leu-Gly was purified from the extract of Streptococcus cremoris H61 by a method that included ammoniumsulfate fractionation, DEAE-cellulose chromatography, hydroxylapatite chromatography, rechromatography on hydroxylapatite and rechromatography on DEAE-cellulose. The purified enzyme exhibited homogeneity in disc electrophoresis. The molecular weight of the enzyme was estimated to be 100, 000 by Sephadex G-150 gel filtration. The enzyme exhibited optimum pH at 8.0 and was stable up to 50°C. It was activated by Co2+ and inhibited by EDTA, 1, 10-phenanthroline and bestatin. The Km value for L-Leu-Gly was estimated to be 5.0 mM. The enzyme showed a wide range of specificity on dipeptides but hardly hydrolyzed tripeptides.