Affiliation:
1. Department of Microbiology, School of Medicine, Indiana University, Indianapolis, Indiana 46202
Abstract
Mutants of
Escherichia coli
K-12 which grow on butyrate and valerate were studied with respect to uptake of these substrates. To utilize short-chain and medium-chain fatty acids,
E. coli
must synthesize the β-oxidation enzymes constitutively. In addition, growth on the C
4
and C
5
acids requires a second mutation which permits entry of these substrates. At
p
H 5, both in the parent and mutant strains, butyrate and valerate penetrate as the undissociated acids but appear not to be activated and thus inhibit growth. At
p
H 7, the parent strain is not permeable to the anions, whereas the mutant concentrates these substrates. There appear to be two components of the uptake system, a nonspecific diffusion component and an energy-linked activating enzyme. Two mutant types which take up short-chain fatty acids are described. One synthesizes the uptake system constitutively and is inhibited by 4-pentenoate when cultured on acetate. In the other, the uptake system is inducible, and the strain is pentenoate-resistant when grown on acetate but pentenoate-sensitive when cultured on butyrate or valerate.
Publisher
American Society for Microbiology
Subject
Molecular Biology,Microbiology
Cited by
24 articles.
订阅此论文施引文献
订阅此论文施引文献,注册后可以免费订阅5篇论文的施引文献,订阅后可以查看论文全部施引文献