Activation of boar proacrosin is effected by processing at both N- and C-terminal portions of the zymogen molecule.
A mixture of 55 and 53 kDa boar proacrosins was autoactivated at pH 8.5 to produce a 43 kDa intermediate form and a 35 kDa mature acrosin, and each of four forms of (pro)acrosins was isolated. Analysis of the N-terminal sequences of the two proacrosins indicated the existence of a segment corresponding to the acrosin light chain at the N-terminal end of the zymogen. Two N-terminal sequences identical with those of the light and heavy chains were found in the intermediate form and mature acrosin. The proacrosins and the intermediate contained many more proline residues than the mature enzyme. These results indicate that the activation of boar acrosin zymogen is achieved by the removal of a C-terminal segment rich in proline residues and by the cleavage of the Arg23-Val24 bond leading to the formation of the light and heavy chains.
Baba
T
T
Institute of Applied Biochemistry, University of Tsukuba, Japan.
Michikawa
Y
Y
Kawakura
K
K
Arai
Y
Y
D000176:Acrosin / Q000378:metabolism*; D000595:Amino Acid Sequence; D000596:Amino Acids / Q000032:analysis; D000818:Animals; D002851:Chromatography, High Pressure Liquid; D004591:Electrophoresis, Polyacrylamide Gel; D004789:Enzyme Activation; D004792:Enzyme Precursors / Q000378:metabolism*; D006863:Hydrogen-Ion Concentration; D008297:Male; D008969:Molecular Sequence Data; D008970:Molecular Weight; D010446:Peptide Fragments / Q000378:metabolism; D011392:Proline / Q000032:analysis; D012697:Serine Endopeptidases / Q000378:metabolism*; D013552:Swine
D000596:Amino Acids; D004792:Enzyme Precursors; D010446:Peptide Fragments; D011392:Proline; D012697:Serine Endopeptidases; C022438:proacrosin; D000176:Acrosin