Isolation of mutants lacking branched-chain amino acid transaminase
Jones, C.; Moore, E.E.
Somatic Cell Genetics 2(3): 235-243
1976
ISSN/ISBN: 0098-0366 PMID: 1028171 DOI: 10.1007/bf01538962
Accession: 040523632
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Variants of the Chinese hamster ovary cell have been isolated which can no longer grow when valine, leucine, or isoleucine is replaced in the culture medium by its respective alpha-keto acid: alpha-ketoisovaleric acid, alpha-ketoisocaproic acid, or alpha-keto-beta-methylvaleric acid. These variants lack branched-chain amino acid transaminase activity. Evidence is presented indicating these variants to be single gene mutants. Genetic evidence is also presented confirming previous biochemical evidence that a single enzyme carries out transaminase functions on valine, leucine, and isoleucine. The branched-chain transaminase-deficient (trans-) mutants can be reverted to wild-type behavior by treatment with mutagenic agents. These mutants promise to be useful in exploring regulatory mechanisms in biochemical, genetic, and cancer research.
