title: A novel missense mutation in human lactate dehydrogenase B-subunit gene.
abstract: Reduced activity of serum lactate dehydrogenase (LDH; EC 1.1.1.27) was found in a male medical student during practical examinations of his own blood. Serum LDH isoenzyme pattern showed reductions in activities of the isoenzymes with lower subunit A/B ratios such as LDH1 and LDH2. These findings were indicative of a partial LDH-B subunit deficiency, which was confirmed in erythrocyte hemolysates by Western blotting. Polymerase chain reaction (PCR)-based DNA sequence analysis of the LDH-B subunit gene revealed a heterozygous nucleotide change: a guanine to adenine substitution in codon 69 (GGG --> GAG) at the third exon of the LDH-B subunit gene that resulted in a glycine to glutamic acid substitution (G69E). The mutation was confirmed by PCR-restriction fragment length polymorphism (RFLP) analysis using a mismatched primer to introduce a new NcoI restriction site. The same heterozygous mutation was found in his mother but not in other family members. This mutation involves a residue belonging to alphaC helix in LDH-B subunit protein molecule that functions as an interface for other subunits.
authors.affiliation: Central Clinical Laboratory, Nara Medical University Hospital, Shijo-Cho 840, Kashihara, Nara 634-8522, Japan.
authors.forename: T
authors.initials: T
authors.lastname: Takatani
authors.forename: N
authors.initials: N
authors.lastname: Takaoka
authors.forename: M
authors.initials: M
authors.lastname: Tatsumi
authors.forename: H
authors.initials: H
authors.lastname: Kawamoto
authors.forename: Y
authors.initials: Y
authors.lastname: Okuno
authors.forename: K
authors.initials: K
authors.lastname: Morita
authors.forename: T
authors.initials: T
authors.lastname: Masutani
authors.forename: K
authors.initials: K
authors.lastname: Murakawa
authors.forename: Y
authors.initials: Y
authors.lastname: Okamoto
mesh_terms: D000328:Adult; D001483:Base Sequence; D015153:Blotting, Western; D006579:Heterozygote; D006801:Humans; D007527:Isoenzymes / Q000097:blood / Q000737:chemistry / Q000172:deficiency / Q000235:genetics; D007770:L-Lactate Dehydrogenase / Q000097:blood / Q000737:chemistry* / Q000172:deficiency / Q000235:genetics*; D008297:Male; D020125:Mutation, Missense / Q000235:genetics*; D016133:Polymerase Chain Reaction; D012150:Polymorphism, Restriction Fragment Length; D021122:Protein Subunits
chemical_list: D007527:Isoenzymes; D021122:Protein Subunits; D007770:L-Lactate Dehydrogenase