Focarelli R, Cacace M G, Seraglia R, Rosati F
Department of Evolutionary Biology, University of Siena, Italy.
Biochem Biophys Res Commun. 1997 May 8;234(1):54-8. doi: 10.1006/bbrc.1997.6576.
The male reproductive system of the mollusc bivalve Unio elongatulus contains two distinct forms of alpha-L-fucosidase, one present in the gonad fluid and a second one associated with the sperm plasma membrane. Both activities were purified to homogeneity. The soluble seminal plasma enzyme had an oligomeric MW of 56 kDa as determined by MALDI-TOF mass spectrometry, whereas the enzyme purified from sperm plasma membranes had an MW of 68 kDa. Analyzed by lectin blotting with ConA and PNA, the 68 kDa enzyme did not bind either lectin, whereas the 56 kDa form bound ConA only. Both fucosidases followed a Michaelis-Menten kinetics with the K(m) of the sperm-bound enzyme being 7.1 x 10(-4) M and that of the seminal enzyme being 9.1 x 10(-4) M. Both had a pH optimum of 5.0.
双壳软体动物长形珠蚌的雄性生殖系统包含两种不同形式的α-L-岩藻糖苷酶，一种存在于性腺液中，另一种与精子质膜相关。两种活性均被纯化至同质。通过基质辅助激光解吸电离飞行时间质谱法测定，可溶性精浆酶的寡聚体分子量为56 kDa，而从精子质膜纯化的酶分子量为68 kDa。用刀豆球蛋白A（ConA）和花生凝集素（PNA）进行凝集素印迹分析，68 kDa的酶不与任何一种凝集素结合，而56 kDa的形式仅与ConA结合。两种岩藻糖苷酶均遵循米氏动力学，精子结合酶的K(m)为7.1×10(-4) M，精浆酶的K(m)为9.1×10(-4) M。两者的最适pH均为5.0。
