Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: EC:3.4.21.4 (trypsin)
 42,187 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Antibodies prepared against chemically synthesized peptides predicted from the DNA sequence have been used to detect human mitochondrial gene products. In particular, antibodies directed against either the NH2-terminal decapeptide or the COOH-terminal undecapeptide of cytochrome c oxidase subunit II (COII) were both very effective in immunoprecipitating the previously identified COII polypeptide from an SDS lysate of mitochondria from HeLa cells. Similarly, antibodies directed against the COOH-terminal nonapeptide of the putative polypeptide encoded in the unidentified reading frame A6L, which overlaps the ATPase 6 gene, immunoprecipitated specifically a component (#25) of the HeLa cell mitochondrial translation products; antibodies directed against the NH2-terminal octapeptide also precipitated protein 25, although less efficiently. The size of protein 25, as estimated from its electrophoretic mobility, is compatible with its being the unidentified reading frame A6L product. Furthermore, a fingerprinting analysis of this protein after trypsin digestion has given results consistent with this identification.
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PMID:Antibodies against synthetic peptides reveal that the unidentified reading frame A6L, overlapping the ATPase 6 gene, is expressed in human mitochondria. 630 89

The catalytic sector, F1, and the membrane sector, F0, of the mitochondrial ATP synthase complex are joined together by a 45-A-long stalk. Knowledge of the composition and structure of the stalk is crucial to investigating the mechanism of conformational energy transfer between F0 and F1. This paper reports on the near neighbor relationships of the stalk subunits with one another and with the subunits of F1 and F0, as revealed by cross-linking experiments. The preparations subjected to cross-linking were bovine heart submitochondrial particles (SMP) and F1-deficient SMP. The cross-linkers were three reagents of different chemical specificities and different lengths of cross-linking from zero to 10 A. Cross-linked products were identified after gel electrophoresis of the particles and immunoblotting with subunit-specific antibodies to the individual subunits alpha, beta, gamma, delta, OSCP, F6, A6L, a (subunit 6), b, c, and d. The results suggested that the two b subunits form the principal stem of the stalk to which OSCP, d, and F6 are bound independent of one another. Subunits b, OSCP, d, and F6 cross-linked to alpha and/or beta, but not to gamma or delta. The COOH-terminal half of A6L, which is extramembranous, cross-linked to d but not to any other stalk or F1 subunit. No cross-links of subunits a and c with any stalk or F1 subunits were detected. In F1-deficient SMP, cross-linked b+b and d+F6 dimers appeared, and the extent of cross-linking between b and OSCP diminished greatly. The addition of F1 to F1-deficient particles appeared to reverse these changes. Treatment of F1-deficient particles with trypsin rapidly hydrolyzed away OSCP and F6, fragmented b to membrane-bound 18-, 12-, and 8-9-kDa antigenic fragments, which cross-linked to d and/or with one another. Trypsin also removed the COOH-terminal part of A6L, but the remainder still cross-linked to subunit d. Models showing the near neighbor relationships of the stalk subunits with one another and with the alpha and beta subunits at a level near the proximal end (bottom) of F1 and at the membrane-matrix interface are presented.
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PMID:ATP synthase complex. Proximities of subunits in bovine submitochondrial particles. 783 33