Cloning, expression, and characterization of a class-mu glutathione transferase from human muscle, the product of the GST4 locus

Journal Article · Wed May 15 00:00:00 EDT 1991 · Proceedings of the National Academy of Sciences of the United States of America; (United States)

DOI:https://doi.org/10.1073/pnas.88.10.4443· OSTI ID:6057486

Vorachek, W R; Pearson, W R; Rule, G S ^[1]

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1. Univ. of Virginia, Charlottesville (United States)

A class-mu glutathione transferase cDNA clone, GTHMUS, was isolated from human myoblasts and its sequence was determined. The sequence predicts a protein of molecular weight 25,599 whose 24 amino-terminal residues are identical to those of the class-mu isoenzyme expressed from the GST4 locus. The GTHMUS cDNA shares 93.7% nucleotide sequence identity with a human liver cDNA clone, GTH411, that is encoded at the GST1 locus. Comparison of the liver and muscle cDNA sequences shows two regions of remarkable sequence conservation: a 140-nucleotide region in the 5{prime} coding portion of the molecule that has a single silent nucleotide substitution, and a 550-nucleotide region, including the entire 3{prime} noncoding region, that has only three nucleotide substitutions or deletions. This sequence conservation suggests that gene conversion has occurred between the human GST1 and GST4 glutathione transferase gene loci. The human muscle and liver glutathione transferase clones GTHMUS and GTH411 have been expressed in Escherichia coli. The kinetic mechanism of the muscle enzyme was examined in product inhibition studies. The inhibition patterns are best modeled by a steady-state ordered bi-bi reaction mechanism. Glutathione is the first substrate bound and chloride ion is the first product released. Chloride ion inhibits the muscle enzyme.

• OSTI ID: 6057486
• Journal Information: Proceedings of the National Academy of Sciences of the United States of America; (United States), Journal Name: Proceedings of the National Academy of Sciences of the United States of America; (United States) Vol. 88:10; ISSN PNASA; ISSN 0027-8424
• Country of Publication: United States
• Language: English

Related Subjects

550200* -- Biochemistry
59 BASIC BIOLOGICAL SCIENCES
AMINO ACID SEQUENCE
ANIMALS
BODY
CLONING
DIGESTIVE SYSTEM
DNA
DNA HYBRIDIZATION
DNA SEQUENCING
DNA-CLONING
DRUGS
ENZYMES
GLANDS
GLUTATHIONE
HYBRIDIZATION
ISOENZYMES
LIVER
MAMMALS
MAN
MOLECULAR STRUCTURE
MUSCLES
NUCLEIC ACIDS
ORGANIC COMPOUNDS
ORGANS
PEPTIDES
POLYPEPTIDES
PRIMATES
PROTEINS
RADIOPROTECTIVE SUBSTANCES
RECOMBINANT DNA
STRUCTURAL CHEMICAL ANALYSIS
TRANSFERASES
VERTEBRATES