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Biology of Reproduction, Vol 6, 30-39, Copyright © 1972 by Society for the Study of Reproduction
1 Department of Biochemistry, University of Georgia, Athens, Georgia 30601 Acrosin is a proteolytic enzyme extractable from sperm acrosomes and essential for
penetration of the zona pellucida of the ovum by spermatozoa. It has properties in common
with both trypsin and plasmin having an optimum pH of 8.0, hydrolyzing benzoyl arginine
ethyl ester (BAEE) and tosyl arginine methyl ester (TAME) but not benzoyl tyrosine ethyl
ester (BTEE), or acetyl tyrosine ethyl ester (ATEE), being stimulated by calcium ions and
stable at pH 3.0. Acrosin differs from pancreatic trypsin in that it hydrolyzes BAEE more
rapidly than TAME, is less effectively inhibited by ovomucoid and pancreatic trypsin inhibitor, has a higher molecular weight, undergoes rapid loss of activity even in the presence
of calcium and produces fewer peptides on incubation with oxidized ribonuclease. One of
two trypsin inhibitors isolated from guinea pig seminal vesicles inhibits acrosin and trypsin
but not plasmin, whereas the other inhibits all three enzymes. Acrosin further differs from
plasmin in that it has a different molecular weight and is more unstable. Inhibition by diisopropyl fluorophosphate and tosyl lysine chloromethyl ketone shows a similarity to trypsins
and lack of inhibition by tosyl phenylalanine chloromethyl ketone indicates that acrosin is
not chymotrypsin-like. The enzyme is also inhibited by soybean trypsin inhibitor. Acrosin
appears to be a unique proteolytic enzyme and therefore deserves a specific name.
This article has been cited by other articles:
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L. J. D. Zaneveld, B. M. Dragoje, and G. F. B. Schumacher Acrosomal Proteinase and Proteinase Inhibitor of Human Spermatozoa Science, August 25, 1972; 177(4050): 702 - 703. [Abstract] [PDF] |
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