title: Chymotrypsin-like enzymes are involved in sperm penetration through the vitelline coat of Ciona intestinalis egg.
abstract: In Ciona intestinalis, sperm penetration through the egg vitelline coat is an essential event of fertilization. We investigated whether trypsin- and chymotrypsin-like enzymes are involved in this event. Inhibitors and peptide substrates for chymotrypsin-like enzymes blocked the overall process of fertilization in a concentration-dependent manner. The inhibitory activity was specifically exerted on the step of sperm penetration. Chymotrypsin-like protease activity was identified in spermatozoa with the fluorogenic synthetic substrate Suc-Ala-Ala-Phe-AMC, which was the most effective substrate in blocking sperm penetration. These data indicate that a chymotrypsin-like protease activity is a sperm lysin of Ciona intestinalis.
authors.affiliation: Institute of Protein Biochemistry and Enzymology, CNR, Napoli, Italy.
authors.forename: M R
authors.initials: MR
authors.lastname: Pinto
authors.forename: M
authors.initials: M
authors.lastname: Hoshi
authors.forename: R
authors.initials: R
authors.lastname: Marino
authors.forename: A
authors.initials: A
authors.lastname: Amoroso
authors.forename: R
authors.initials: R
authors.lastname: De Santis
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D053818:Chymases; D002938:Ciona intestinalis / Q000502:physiology*; D005260:Female; D005307:Fertilization in Vitro / Q000187:drug effects; D008297:Male; D008969:Molecular Sequence Data; D009088:Mucoproteins / Q000494:pharmacology*; D012697:Serine Endopeptidases / Q000494:pharmacology*; D013084:Sperm-Ovum Interactions / Q000187:drug effects*; D013094:Spermatozoa / Q000201:enzymology*; D013379:Substrate Specificity; D014817:Vitelline Membrane / Q000187:drug effects*
chemical_list: D009088:Mucoproteins; C010393:lysin, gastropoda; D012697:Serine Endopeptidases; D053818:Chymases