Salmonella typhimurium peptidase active on carnosine
| Autor: | P E Hartman, D R Dembinski, C G Miller, M Kirsh |
|---|---|
| Rok vydání: | 1978 |
| Předmět: |
Salmonella typhimurium
Dipeptidase Mutant Carnosine Peptide medicine.disease_cause Microbiology chemistry.chemical_compound Transduction Genetic medicine Molecular Biology Histidine chemistry.chemical_classification Manganese Mutation biology PEPD Cobalt Dipeptides Hydrogen-Ion Concentration Molecular biology Kinetics Enzyme Genes chemistry Biochemistry biology.protein Research Article Peptide Hydrolases |
| Zdroj: | Journal of Bacteriology. 134:361-374 |
| ISSN: | 1098-5530 0021-9193 |
| DOI: | 10.1128/jb.134.2.361-374.1978 |
| Popis: | Wild-type Salmonella typhimurium can use carnosine (beta-alanyl-L-histidine) as a source of histidine, but carnosine utilization is blocked in particular mutants defective in the constitutive enzyme peptidase D, the product of the pepD gene. Biochemical evidence for assigning carnosinase activity to peptidase D (a broad-specificity dipeptidase) includes: (i) coelution of carnosinase and dipeptidase activity from diethylaminoethyl-cellulose and Bio-Gel P-300 columns; (ii) coelectrophoresis of carnosinase and dipeptidase on polyacrylamide gels; and (iii) inactivation of carnosinase and dipeptidase activities at identical rates at both 4 and 42 degrees C. Genetic evidence indicates that mutations leading to loss of carnosinase activity map at pepD. Several independent pepD mutants have been isolated by different selection procedures, and the patterns of peptide utilization of strains carrying various pepD alleles have been studied. Many pepD mutations lead to the production of partially active peptidase D enzymes with substrate specificities that differ strikingly from those of the wild-type enzyme. The growth yields of carnosinase-deficient strains growing in Difco nutrient broth indicate that carnosine is the major utilizable source of histidine in this medium. |
| Databáze: | OpenAIRE |
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