Characterization of human semen alpha-L-fucosidases.
Human semen contains a large amount of alpha-L-fucosidase activity, the great majority of which is found in the seminal fluid. Immunocytochemical studies indicate that a small amount of semen fucosidase activity is present on the sperm plasma membrane, primarily in the posterior head region. Subcellular fractionation studies also indicate that sperm alpha-L-fucosidase is present in the plasma membrane-enriched fraction. Comparative characterization of human seminal fluid and sperm alpha-L-fucosidases indicates that seminal fluid alpha-L-fucosidase has a broad pH optimum curve with a number of near-equal maxima between pH 4.8 and 7.0 while sperm fucosidase has a major optimum between pH 3.4 and 4.0. Isoelectric focusing indicates that seminal fluid alpha-L-fucosidase contains three to six isoforms with isoelectric points (pI) of 5-7 while sperm fucosidase contains two distinct isoforms with pI values of 5. 2 +/- 0.2 and 7.0 +/- 0.2. Western blotting indicates that seminal fluid fucosidase contains a major protein band with a molecular mass ratio (M(r)) of approximately 56 kDa while sperm fucosidase contains a major protein band of approximately 51 kDa. The overall results indicate the presence of a low-abundance, plasma membrane-associated human sperm alpha-L-fucosidase, which is different in its properties from human seminal fluid alpha-L-fucosidase(s), and whose function is not yet known.
Alhadeff
J A
JA
Department of Chemistry, 111 Research Drive, Lehigh University, Bethlehem, PA 18015, USA.
Khunsook
S
S
Choowongkomon
K
K
Baney
T
T
Heredia
V
V
Tweedie
A
A
Bean
B
B
D015153:Blotting, Western; D002462:Cell Membrane / Q000201:enzymology; D004795:Enzyme Stability; D006801:Humans; D006863:Hydrogen-Ion Concentration; D007150:Immunohistochemistry; D007525:Isoelectric Focusing; D007527:Isoenzymes / Q000378:metabolism; D007700:Kinetics; D008297:Male; D012016:Reference Values; D012661:Semen / Q000201:enzymology*; D013094:Spermatozoa / Q000166:cytology / Q000201:enzymology*; D013347:Subcellular Fractions; D005644:alpha-L-Fucosidase / Q000032:analysis*
D007527:Isoenzymes; D005644:alpha-L-Fucosidase