Biomaterial Database

Variation in the expression of Mu-class glutathione S-transferase isoenzymes from human skeletal muscle. Evidence for the existence of heterodimers. 1991

A J Hussey, and L A Kerr, and A D Cronshaw, and D J Harrison, and J D Hayes

University of Edinburgh Department of Clinical Chemistry, Royal Infirmary, U.K.

The cytosolic glutathione S-transferases (GST) from human skeletal muscle were purified by a combination of affinity chromatography and anion-exchange chromatography followed by either chromatofocusing or hydroxyapatite chromatography. Pi-class and Mu-class GST, but not Alpha-class GST, were isolated from muscle. In addition to a Pi-class GST subunit, which exists as a homodimer, this tissue also contains a total of three distinct neutral-type Mu-class GST subunits, which hybridize to form homodimers or heterodimers. The neutral-type subunits are referred to as N1-N3 and are defined by the decreasing isoelectric points of the homodimers; GST N1N1, N2N2 and N3N3 have estimated pI values of 6.1, 5.3 and less than 5.0 respectively. SDS/PAGE showed that N1, N2 and N3 have Mr values of 26,700, 26,000 and 26,300 respectively. The N1, N2 and N3 subunits are catalytically distinct, with N1 possessing a high activity for trans-4-phenylbut-3-en-2-one and N2 having high activity with 1,2-dichloro-4-nitrobenzene. In skeletal muscle the expression of the N1 subunit, but not of N2 and N3 subunits, was found to differ from specimen to specimen. The N1 subunit was absent from about 50% of samples examined, and the purification results from two different specimens are presented to illustrate this inter-individual variation. Skeletal muscle from one individual (M1), which did not express N1, contained only GST N2N2, N2N3 and pi, whereas the second sample examined (M2) contained GST N1N2, N2N2 and N2N3 as well as GST pi. N-Terminal amino acid sequence analysis supported the electrophoretic evidence that the N2 subunit in GST N1N2, N2N2 and N2N3 represents the same polypeptide. The peptides obtained from CNBr digests of N2 were subjected separately to automated amino acid sequencing, and the results indicate that N2 is distinct but closely related to the protein encoded by the human Mu-class cDNA clone GTH4 [DeJong, Chang, Whang-Peng, Knutsen & Tu (1988) Nucleic Acids Res. 16, 8541-8554]. GST N2N2 is probably identical with GST 4 [Board, Suzuki & Shaw (1988) Biochim. Biophys. Acta 953, 214-217], as over the 24 N-terminal residues of GST 4 there is complete identity between the two enzymes. Our data suggest that the GST 1 and GST 4 loci are part of the same multi-gene family.

UI	MeSH Term	Description	Entries
D007527	Isoenzymes	Structurally related forms of an enzyme. Each isoenzyme has the same mechanism and classification, but differs in its chemical, physical, or immunological characteristics.	Alloenzyme,Allozyme,Isoenzyme,Isozyme,Isozymes,Alloenzymes,Allozymes
D008969	Molecular Sequence Data	Descriptions of specific amino acid, carbohydrate, or nucleotide sequences which have appeared in the published literature and/or are deposited in and maintained by databanks such as GENBANK, European Molecular Biology Laboratory (EMBL), National Biomedical Research Foundation (NBRF), or other sequence repositories.	Sequence Data, Molecular,Molecular Sequencing Data,Data, Molecular Sequence,Data, Molecular Sequencing,Sequencing Data, Molecular
D008970	Molecular Weight	The sum of the weight of all the atoms in a molecule.	Molecular Weights,Weight, Molecular,Weights, Molecular
D009132	Muscles	Contractile tissue that produces movement in animals.	Muscle Tissue,Muscle,Muscle Tissues,Tissue, Muscle,Tissues, Muscle
D011487	Protein Conformation	The characteristic 3-dimensional shape of a protein, including the secondary, supersecondary (motifs), tertiary (domains) and quaternary structure of the peptide chain. PROTEIN STRUCTURE, QUATERNARY describes the conformation assumed by multimeric proteins (aggregates of more than one polypeptide chain).	Conformation, Protein,Conformations, Protein,Protein Conformations
D002846	Chromatography, Affinity	A chromatographic technique that utilizes the ability of biological molecules, often ANTIBODIES, to bind to certain ligands specifically and reversibly. It is used in protein biochemistry. (McGraw-Hill Dictionary of Scientific and Technical Terms, 4th ed)	Chromatography, Bioaffinity,Immunochromatography,Affinity Chromatography,Bioaffinity Chromatography
D003488	Cyanogen Bromide	Cyanogen bromide (CNBr). A compound used in molecular biology to digest some proteins and as a coupling reagent for phosphoroamidate or pyrophosphate internucleotide bonds in DNA duplexes.	Bromide, Cyanogen
D004137	Dinitrochlorobenzene	A skin irritant that may cause dermatitis of both primary and allergic types. Contact sensitization with DNCB has been used as a measure of cellular immunity. DNCB is also used as a reagent for the detection and determination of pyridine compounds.	1-Chloro-2,4-Dinitrobenzene,2,4-Dinitrochlorobenzene,Benzene, 1-Chloro-2,4-Dinitro-,Chlorodinitrobenzene,DNCB,1 Chloro 2,4 Dinitrobenzene,2,4 Dinitrochlorobenzene
D005260	Female		Females
D005810	Multigene Family	A set of genes descended by duplication and variation from some ancestral gene. Such genes may be clustered together on the same chromosome or dispersed on different chromosomes. Examples of multigene families include those that encode the hemoglobins, immunoglobulins, histocompatibility antigens, actins, tubulins, keratins, collagens, heat shock proteins, salivary glue proteins, chorion proteins, cuticle proteins, yolk proteins, and phaseolins, as well as histones, ribosomal RNA, and transfer RNA genes. The latter three are examples of reiterated genes, where hundreds of identical genes are present in a tandem array. (King & Stanfield, A Dictionary of Genetics, 4th ed)	Gene Clusters,Genes, Reiterated,Cluster, Gene,Clusters, Gene,Families, Multigene,Family, Multigene,Gene Cluster,Gene, Reiterated,Multigene Families,Reiterated Gene,Reiterated Genes