The presence of a glycosyl phosphatidylinositol-anchored alpha-mannosidase in boar sperm.
alpha-Mannosidase and beta-galactosidase were released from boar sperm into the medium by treatment with calcium ionophore A23187 or by 0.2% Brij-35/2% acetic acid. About half as much alpha-mannosidase activity as that in the acid extract was recovered by digestion with phosphatidylinositol-specific phospholipase C (PI-PLC), whereas the liberation rate of beta-galactosidase treated with PI-PLC was low. These results suggest that some alpha-mannosidase is anchored in the plasma membrane of the acrosomal region by attachment to the lipid phosphatidylinositol and that beta-galactosidase is localized mainly in the acrosome or integrated in the plasma membrane by a spanning stretch of hydrophobic peptides. beta-Galactosidase, which is present as an oligomers in the acid extract of sperm, dissociated into monomers under weakly alkaline conditions; under acidic conditions, the monomers associated again. No pH-sensitive association-dissociation of alpha-mannosidase was observed.
Kuno
M
M
Graduate School of Science and Technology, Faculty of Science, Chiba University, Japan. mnakano@scichem.s.chiba-u.ac.jp
Yonezawa
N
N
Amari
S
S
Hayashi
M
M
Ono
Y
Y
Kiss
L
L
Sonohara
K
K
Nakano
M
M
D000177:Acrosome / Q000201:enzymology / Q000378:metabolism; D020101:Acrosome Reaction; D000818:Animals; D002462:Cell Membrane / Q000201:enzymology / Q000378:metabolism; D004795:Enzyme Stability; D017261:Glycosylphosphatidylinositols / Q000302:isolation & purification / Q000378:metabolism*; D006863:Hydrogen-Ion Concentration; D008297:Male; D008361:Mannosidases / Q000302:isolation & purification / Q000378:metabolism*; D043265:Phosphatidylinositol Diacylglycerol-Lyase; D054801:Phosphoinositide Phospholipase C; D013094:Spermatozoa / Q000201:enzymology* / Q000378:metabolism; D013552:Swine; D010738:Type C Phospholipases; D043323:alpha-Mannosidase; D001616:beta-Galactosidase / Q000302:isolation & purification / Q000378:metabolism
D017261:Glycosylphosphatidylinositols; D010738:Type C Phospholipases; D054801:Phosphoinositide Phospholipase C; D008361:Mannosidases; D001616:beta-Galactosidase; D043323:alpha-Mannosidase; D043265:Phosphatidylinositol Diacylglycerol-Lyase