Kinetics of inhibition of sperm β‐acrosin activity by suramin

Abstract

Sperm L L-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 L L-acrosins respectively. Surface charge distribution models of boar L L-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 L L-acrosin to bind suramin. ß

Inhibition of Myotoxic Activity of Bothrops asper Myotoxin II by the Anti-trypanosomal Drug Suramin

“…[1][2][3][4] The spectrum of suramin applications now includes the clinical treatment of angiogenesis, carcinomas of the kidney and prostate gland, breast cancer, inhibition of growth factor/receptor interactions, inhibition of human a-thrombin, protein-tyrosine phosphatases, G proteins, merozoite surface protein-1, and acidic and basic fibroblast growth factors. [5][6][7][8][9][10][11][12][13][14] Suramin prevents the development of muscle necrosis induced by some snake venoms, since it inhibits the myotoxic and in vitro neuromuscular blocking activities of Lys49 phospholipases A 2 from Bothrops species. 15,16 Phospholipases A 2 (PLA 2 s: EC 3.1.…”

Soybean lecithin–based extender preserves spermatozoa membrane integrity and fertilizing potential during goat semen cryopreservation

“…After the acrosome 422 reaction, proacrosin is converted to alpha-acrosin, which remains bound to the acrosome. Alpha-acrosin is 423 then auto-catalytically converted into beta-acrosin that is released to the extracellular milieu [45]. …”