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Activities and Properties of Putrescine‐Biosynthetic Enzymes in Vibrio parahaemolyticus
Author(s) -
Yamamoto Shigeo,
Nakao Hiroshi,
Yamasaki Keiko,
Takashina Kimiko,
Suemoto Yasuo,
Shinoda Sumio
Publication year - 1988
Publication title -
microbiology and immunology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.664
H-Index - 70
eISSN - 1348-0421
pISSN - 0385-5600
DOI - 10.1111/j.1348-0421.1988.tb01429.x
Subject(s) - putrescine , agmatine , arginine decarboxylase , vibrio parahaemolyticus , ornithine decarboxylase , biochemistry , enzyme , biology , biosynthesis , ornithine , spermidine , arginine , cadaverine , decarboxylation , arginase , carboxy lyases , amino acid , bacteria , genetics , catalysis
The biosynthetic pathways for putrescine (Put) in Vibrio parahaemolyticus were delineated by measuring activities of the enzymes which would be involved in its biosynthesis. Experiments with labeled arginine and ornithine revealed that both of these amino acids were converted into Put by intact cells. The activities of three enzymes, arginine decarboxylase (ADC), ornithine decarboxylase (ODC), and agmatine ureohydrolase (AUH), were detected in cell extracts. ADC and ODC of V. parahaemolyticus were similar in the following properties to the corresponding enzymes of Escherichia coli : 1) both decarboxylases showed a pH optimum at 8.25 and required pyridoxal phosphate and dithiothreitol for full activity; 2) while ODC was considerably activated by GTP, ADC was only slightly; 3) both decarboxylases were inhibited by polyamines; 4) ADC was inhibited by difluoromethylarginine, a potent inhibitor of bacterial ADC. However, in contrast to the corresponding enzymes of E. coli , the V. parahaemolyticus ADC showed no requirement for Mg 2+ , and the AUH was active over a wide pH range of 8.5–9.5 with a maximum at pH 9.0. Furthermore, in all 6 strains tested, the activity of ADC was obviously high compared with that of ODC, and AUH was present with a relatively high activity. Cultivation of these strains at a suboptimal NaCl concentration (0.5%) resulted in a pronounced increase in both ADC and AUH activities. These observations suggest that the important pathway for Put biosynthesis in V. parahaemolyticus is the decarboxylation of arginine by ADC and the subsequent hydrolysis of its product, agmatine, by AUH.