title: Dansylalanyllysylchloromethyl ketone as a fluorescent probe for localization of acrosin activity in boar and human spermatozoa.
abstract: The localization of acrosin (EC 3.4.21.10) activity in mammalian spermatozoa was investigated by use of the fluorescent site-directed acrosin inhibitor, dansylalanyllysylchloromethyl ketone (DALCK). Fluorescence microscope preparations revealed, after the spermatozoa were subjected to a specific treatment, that acrosin activity is confined specifically to the inner acrosomal membrane (IAM). Spectrofluorometric and fluorescence polarization investigations verified that the fluorescent probe, once it is specifically bound to the treated spermatozoa, lies in a very hydrophobic environment and shows a remarkable reduction of rotational freedom. These results are compatible with the hypothesis that, under the experimental conditions used, active acrosin is tightly bound to the IAM and that the "specificity site" of the acrosin-active center is probably of a highly hydrophobic nature.
mesh_terms: D000176:Acrosin / Q000032:analysis* / Q000037:antagonists & inhibitors / Q000378:metabolism; D000177:Acrosome / Q000201:enzymology; D000590:Amino Acid Chloromethyl Ketones; D000818:Animals; D001665:Binding Sites; D003619:Dansyl Compounds; D010450:Endopeptidases / Q000032:analysis*; D005454:Fluorescence Polarization; D005456:Fluorescent Dyes; D006651:Histocytochemistry; D006801:Humans; D007425:Intracellular Membranes / Q000201:enzymology; D008297:Male; D008565:Membrane Proteins / Q000032:analysis; D008856:Microscopy, Fluorescence; D013050:Spectrometry, Fluorescence; D013094:Spermatozoa / Q000201:enzymology*; D013552:Swine
chemical_list: D000590:Amino Acid Chloromethyl Ketones; D003619:Dansyl Compounds; D005456:Fluorescent Dyes; D008565:Membrane Proteins; C041051:dansylalanyllysine chloromethyl ketone; D010450:Endopeptidases; D000176:Acrosin