Linked Life Data

2109619

Source:http://linkedlifedata.com/resource/pubmed/id/2109619

Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
4
pubmed:dateCreated
1990-5-31
pubmed:abstractText
One of the mouse sperm surface binding sites for zona pellucida ligands exhibits galactosyltransferase (GT) enzyme activity. The present study was undertaken to ascertain whether the GT site behaves as a noncatalytic binding site in its physiological capacity, with no glycosylation of zona ligands, or whether glycosylation of zona ligands is an integral part of sperm-zona binding. The effects of Mn2+, the obligatory cation for GT catalysis, on enzyme activity and sperm-zona binding were examined. With uridine-5'-diphosphogalactose (UDPgal) as galactose donor, and N-acetylglucosamine (GlcNAc) as galactose acceptor, increasing concentrations of Mn2+ in the range of 0.1-10 mM increased GT enzyme activity, with half-maximal activation at 0.65 mM Mn2+ (Vmax = 20 pmol/hr/10(6) cells). In the presence of 0-2 mM Mn2+, sperm-zona binding was inhibited in a concentration-dependent manner; 50% inhibition occurred at 1.25 mM Mn2+. At this concentration, GT enzyme activity was at 65% Vmax. To determine the specificity of the GT site for glycoprotein terminal carbohydrate residues, spermatozoa were incubated with, asialo-ovine submaxillary mucin (N-acetylgalactosamine residues), asialo-, -alpha 1-acid glycoprotein (beta 1-4 galactose residues) ovalbumin (Ov; GlcNAc residues), and asialo-agalacto-/alpha 1-acid glycoprotein (AsAgAGP; GlcN-Ac residues). Only Ov and AsAgAGP acted as acceptors for galactose in the enzyme assay and inhibitors in the sperm-zona binding assay. The kinetics of the interaction of AsAgAGP with the GT site were determined: the Km was 3.6 mg/ml, with Vmax of 33 pmol/hr/10(6) cells.(ABSTRACT TRUNCATED AT 250 WORDS)
pubmed:grant
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Apr
pubmed:issn
1040-452X
pubmed:author
pubmed:issnType
Print
pubmed:volume
25
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
393-9
pubmed:dateRevised
2007-11-14
pubmed:meshHeading
pubmed:year
1990
pubmed:articleTitle
Further characterization of the mouse sperm surface zona-binding site with galactosyltransferase activity.
pubmed:affiliation
Department of Obstetrics and Gynecology, University of Pennsylvania School of Medicine, Philadelphia 19104-6080.
pubmed:publicationType
Journal Article, Research Support, U.S. Gov't, P.H.S.