ISSN:
1574-6968
Source:
Blackwell Publishing Journal Backfiles 1879-2005
Topics:
Biology
Notes:
Abstract Acinetobacter sp. strain 4-CB1 cometabolized 3,4-dichlorobenzoate (3,4-DCB), via 3-chloro-4-hydroxybenzoate (3-C-4-OHB) and 4-carboxy-1,2-benzoquinone, in the presence of 4-chlorobenzoate (4-CB) as a growth substrate. In resting cell incubations, 3,4-DCB acted competitively as an inhibitor with 4-CB metabolism, and as a substrate inhibitor of its own metabolism. The inhibitor constant Ki and the affinity constant Km were 800 and 181 μM, respectively with a maximal rate of 3,4-DCB disappearance of 18.8 nmol 3,4-DCB min−1 (mg protein)−1, in resting cells incubated solely with 3,4-DCB. Resting cells were less tolerant to 3,4-DCB than growing cells, as noted from the inhibition constants (Ki). Moreover, 3-C-4-OHB competitively inhibited 4-hydroxybenzoate monooxygenase by acting as a pseudosubstrate (Ki= 7.3 μM). The next sequential intermediate, 4-carboxy-1,2-benzoquinone, uncompetitively inhibited 4-CB metabolism in resting cell incubations. Thus, 3,4-DCB inhibited its own cometabolism as well as metabolism of 4-CB in Acinetobacter sp. strain 4-CB1.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1111/j.1574-6968.1991.tb04755.x
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