title: Boar acrosin is a two-chain molecule. Isolation and primary structure of the light chain; homology with the pro-part of other serine proteinases.
abstract: Acrosin (EC 3.4.21.10), the major proteinase of mammalian spermatozoa, has been demonstrated to be a two-chain glycoprotein with an Mr-4200 light chain covalently attached to an Mr-37000 heavy chain. Following mercaptolysis of the disulfide bonds, the two chains were separated by high-performance liquid chromatography on a reversed-phase column. Sequence analysis of the isolated light chain (23 amino acid residues) indicated a considerable sequence homology with the bovine chymotrypsinogen activation peptide (6 out of 15 positions with identical amino acids, i.e. 40% identity) and the pro-part of other serine proteinases (17-22% identity), thus suggesting that the acrosin light chain corresponds to the pro-part of the acrosin zymogen. In position 3, the light chain confers a carbohydrate side chain N-glycosidically linked to the acceptor sequence Asn-Xaa-Thr. Evidence is presented that the acrosin light chain is connected via two disulfide bridges to the heavy chain which contains about 320 amino acids including the active-site residues of the proteinase.
mesh_terms: D000176:Acrosin / Q000302:isolation & purification*; D000595:Amino Acid Sequence; D000818:Animals; D002241:Carbohydrates / Q000032:analysis; D055598:Chemical Phenomena; D002621:Chemistry; D010450:Endopeptidases / Q000302:isolation & purification*; D004792:Enzyme Precursors / Q000302:isolation & purification*; D008297:Male; D010446:Peptide Fragments / Q000302:isolation & purification; D012697:Serine Endopeptidases; D013438:Sulfhydryl Compounds / Q000032:analysis; D013552:Swine
chemical_list: D002241:Carbohydrates; D004792:Enzyme Precursors; D010446:Peptide Fragments; D013438:Sulfhydryl Compounds; D010450:Endopeptidases; D012697:Serine Endopeptidases; D000176:Acrosin