Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: EC:6.4.1.1 (pyruvate carboxylase)
 1,516 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Pyruvate carboxylase from Pseudomonas citronellolis is composed of non-identical subunits which include a larger biotin-containing polypeptide (alpha) of Mr = 65,000, and a smaller biotin-free polypeptide (beta) of Mr = 54,000. We have investigated these two polypeptides by analyzing their amino acid composition, cyanogen bromide peptide maps, and immunochemistry. The results showed that the subunits of the enzyme have quite different properties. Antibodies prepared against the polypeptides were used as probes of the catalytic functions of the subunits. Immunotitration studies indicated that only anti-alpha inhibited enzyme activity. The antibiotin fraction of this antibody population was removed by passage through biotin-Sepharose (anti-alpha'). Titration curves using anti-alpha' showed identical inhibition when total pyruvate carboxylase activity, ATP/Pi exchange activity, and pyruvate/oxalacetate exchange activity were measured, suggesting that both active sites are located on the alpha polypeptide. The arrangement of the subunits in the quaternary structure was investigated by means of the surface probe carbonic anhydrase linked to toluene isocyanate, and by partial digestion experiments with trypsin, chymotrypsin, and pronase. The results indicated that the alpha polypeptides are on the outside of the molecule and the beta polypeptides are the internal subunits.
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PMID:Characterization of the subunit structure of pyruvate carboxylase from Pseudomonas citronellolis. 679 93

Pyruvate carboxylase (PC) [EC 6.4.1.1] is a biotin-dependent carboxylase that catalyses the conversion of pyruvate to oxaloacetate. Here we have determined the complete nucleotide sequence encoding chicken PC (cPC) by screening a liver cDNA library, by RT-PCR of poly(A)(+) RNA, and by PCR of genomic DNA. The full-length transcript contains an open reading frame of 3537 nucleotides, including the stop codon, encoding a polypeptide of 1178 amino acids with M(r) of 127,262. The amino acid sequence of cPC shows approximately 77% identity to mammalian PC. Limited proteolysis of pure cPC with chymotrypsin yields a major stable 75 kDa C-terminal peptide, including the biotinyl domain and a minor, unstable 39 kDa N-terminal peptide. Northern analysis of poly(A)(+) RNA isolated from chicken liver has shown that cPC's mRNA is approximately 5 kb in length, including a very long 3'-untranslated region.
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PMID:Molecular cloning and domain structure of chicken pyruvate carboxylase. 1215 Sep 61