title: Purification and characterization of a vitelline coat lysin from Ciona intestinalis spermatozoa.
abstract: In Ciona intestinalis a chymotrypsin-like activity is involved in sperm penetration of the egg vitelline coat. A chymotrypsin-like enzyme has been purified from spermatozoa by a protocol including ion exchange chromatography, gel filtration, and native polyacrylamide gel electrophoresis. The purified enzyme resulted homogeneous when analyzed by SDS-PAGE. The molecular weight of the chymotrypsin-like enzyme was estimated to be 35 kDa by gel filtration and 24 KDa by SDS-PAGE in nonreducing conditions. The pH optimum of the enzyme is 8.4 and its activity is enhanced by Ca2+. It shows the highest activity towards the synthetic substrate Suc-Ala-Ala-Pro-Phe-AMC. Furthermore, by electron microscopy, the purified enzyme affects the structure of egg vitelline coat, and thus it fulfills one of the criteria of a lysin.
authors.affiliation: Department of Cell and Developmental Biology, Stazione Zoologica A. Dohrn, Napoli, Italy.
authors.forename: R
authors.initials: R
authors.lastname: Marino
authors.forename: R
authors.initials: R
authors.lastname: De Santis
authors.forename: N
authors.initials: N
authors.lastname: Hirohashi
authors.forename: M
authors.initials: M
authors.lastname: Hoshi
authors.forename: M R
authors.initials: MR
authors.lastname: Pinto
authors.forename: N
authors.initials: N
authors.lastname: Usui
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D002852:Chromatography, Ion Exchange; D002918:Chymotrypsin / Q000378:metabolism; D002938:Ciona intestinalis; D004591:Electrophoresis, Polyacrylamide Gel; D004798:Enzymes / Q000302:isolation & purification* / Q000378:metabolism; D008297:Male; D008969:Molecular Sequence Data; D009088:Mucoproteins / Q000302:isolation & purification* / Q000378:metabolism; D013094:Spermatozoa / Q000201:enzymology*; D014817:Vitelline Membrane / Q000378:metabolism* / Q000648:ultrastructure
chemical_list: D004798:Enzymes; D009088:Mucoproteins; C010393:lysin, gastropoda; D002918:Chymotrypsin