Kinetics of inhibition of sperm beta-acrosin activity by suramin.
Sperm beta-acrosin activity is inhibited by suramin, a polysulfonated naphthylurea compound with therapeutic potential as a combined antifertility agent and microbicide. A kinetic analysis of enzyme inhibition suggests that three and four molecules of suramin bind to one molecule of ram and boar beta-acrosins respectively. Surface charge distribution models of boar beta-acrosin based on its crystal structure indicate several positively charged exosites that represent potential 'docking' regions for suramin. It is hypothesised that the spatial arrangement and distance between these exosites determines the capacity of beta-acrosin to bind suramin.
Hermans
Josephine M
JM
Department of Biochemistry and Molecular Biology, School of Pharmacy and Molecular Sciences, James Cook University, Townsville, Qld 4811, Australia. josephine.hermans@jcu.edu
Haines
Dianne S
DS
James
Peter S
PS
Jones
Roy
R
D000176:Acrosin / Q000737:chemistry / Q000378:metabolism*; D000818:Animals; D001665:Binding Sites; D004305:Dose-Response Relationship, Drug; D005306:Fertilization; D007700:Kinetics; D008297:Male; D008956:Models, Chemical; D008958:Models, Molecular; D011485:Protein Binding; D012697:Serine Endopeptidases / Q000378:metabolism; D012756:Sheep; D013094:Spermatozoa / Q000378:metabolism*; D013498:Suramin / Q000494:pharmacology*; D013552:Swine; D015044:Zona Pellucida / Q000378:metabolism
D013498:Suramin; D012697:Serine Endopeptidases; D000176:Acrosin