Masao Isono

Asparaginase and Glutaminase Activities of Micro-organisms

Summary: l-Asparaginase and l-glutaminase activities were detected in many microorganisms and the distribution of these activities was found to be related to the classification of micro-organisms. Among 464 bacteria, the activities occurred in many Gram-negative bacteria and in a few Gram-positive bacteria. Most members of the family Enterobacteri-aceae possessed l-asparaginase. l-Asparaginase and l-glutaminase occurred together in a large proportion of pseudomonads. Among Gram-positive bacteria many strains of Bacillus pumilus showed strong l-asparaginase activity. Amidase activities were also observed in several strains in other families. l-Asparaginase activity was not detected in culture filtrates of 261 strains of species of the genera Streptomyces and Nocardia, but l-asparaginase and l-glutaminase were detected when these organisms were sonicated. The amidase activities in culture filtrates of 4158 fungal strains were tested. All the strains of Fusarium species formed l-asparaginase. Organisms of the genera Hypomyces and Nectria, which are regarded as the perfect stage of the genus Fusarium, also formed l-asparaginase. Several Penicillium species formed l-asparaginase. Two organisms of the family Moniliaceae formed l-glutaminase together with l-asparaginase, and a fewascomycetous fungi formed l-asparaginase or l-glutaminase. Among 1326 yeasts, l-asparaginase or l-glutaminase occurred frequently in certain serological groups of yeasts: VI (Hansenula) group, Cryptococcus group and Rhodotorula group. Many strains of Sporobolomyces species also showed l-asparaginase activity. Several strains of Cryptococcus and Rhodotorula group possessed l-glutaminase and l-asparaginase. l-Glutaminase alone was formed in many strains of Candida scottii and Cryptococcus albidus, both of which are related to Basidiomycetes.

Serratia Protease: Part I. Purification and General Properties of the Enzyme†

A strain of Serratia, isolated from an intestinal canal of a silkworm, produced a large quantity of protease. The enzyme was extracellular and was named Serratiopeptidase, tentatively. Protease pro...

Serratia Protease:Part III. Characteristics of the Enzyme as Metalloenzyme

Protease from a strain of Serratia contained one gram atom of zinc ion per mole and the zinc ion was essential for the activity. Also zinc-free apoenzyme was isolated as a crystalline form from the native-enzyme. Several metalloenzymes were prepared by the addition of corresponding metal ions to the apoenzyme. Studies on activities toward the hydrolysis of casein showed that relative activities of native- (zinc), cobalt- and manganese-enzyme were 1.0, 1.2 and 0.8, respectively. Toward the hydrolysis of hippurylleucinamide, however, specific activity of cobalt-enzyme was about 10 times that of the native- (zinc-) enzyme. Spectroscopic studies did not reveal any significant differences in conformations among native-enzyme, apoenzyme and the other metalloenzymes.

Serratia Protease:Part II. Substrate Specificity of the Enzyme

The substrate specificity of Serratia protease was determined using various synthetic substrates. The enzyme did not participate in the hydrolysis of di- and tri-peptides except benzoylglycylleucinamide which was split at a limited rate into hippuric acid and leucinamide. The enzyme action on larger peptides was also studied. The enzyme cleaved the gly-leu bond in eledoisin related peptide and the gly-phe bond in bradykinin. The enzyme split oxidized insulin B-chain at twelve different peptide bonds.

Chemical structure of an acidic polysaccharide produced by serratia piscatorum

Abstract The acidic polysaccharide of Serratia piscatorum consists of L -rhamnopyranosyl, D -galactopyranosyl, and D -galactopyranosyluronic acid residues in the molar ratio of 2:1:1. Some of the D -galactopyranosyluronic acid residues are acetylated at O-2 or O-3, or both. Smith degradation and methylation analysis indicated that the L -rhamnopyranosyl, D -galactopyranosyl, and D -galactopyranosyluronic acid residues are substituted with glycosidic linkages at O-3, O-3, and O-4, respectively. Partial acid hydrolysis of the native polysaccharide gave four acidic oligosaccharides, each of which was isolated and characterized, suggesting the following tetrasaccharide repeating unit: →3)- L -Rha p -(1→4)- D -GalA p -(1→3)- L -Rha p -(1→3)- D -Gal p -(1→.

A bacteriolytic enzyme from Chaetomium globosum, a marine-isolate

SummaryWhen a marine-isolate, Chaetomium globosum was cultivated in a medium with an increased MgCl2 content, a bacteriolytic enzyme was extracellularly produced. The enzyme was purified approximately 130-fold. It lyzed Staphylococcus aureus, Micrococcus lysodeikticus and several other Gram-positive bacteria. Optimal pH and temperature for the lysis were 8.0 and 37°C, respectively. The enzyme was heat-labile with maximum stability at neutral pH. Enzymatic activity was greatly stimulated by NaCl and CaCl2 with maximum activity obtained in the presence of 0.1 M NaCl and 0.003 M to 0.005 M CaCl2. The activity was stimulated by SH-compounds and was inhibited by SH-reactants.The enzyme is an N-acetylhexosaminidase.