title: The presence of a high-Km hexokinase activity in dog, but not in boar, sperm.
abstract: The presence of a high-Km hexokinase activity was tested in both dog and boar spermatozoa. Hexokinase kinetics from dog extracts showed the presence of a specific activity (dog-sperm glucokinase-like protein, DSGLP), in the range of glucose concentrations of 4-10 mM, whereas boar sperm did not show any DSGLP activity. Furthermore, dog-sperm cells, but not those of boar, showed the presence of a protein which specifically reacted against a rat-liver anti-glucokinase antibody. This protein also had a molecular weight equal to that observed in rat-liver extracts, suggesting a close similarity between both the proteins. This glucokinase-like protein was distributed in the peri- and post-acrosomal zones of the head, and the midpiece and principal piece of tail of dog spermatozoa. These results indicate that dog spermatozoa have functional high-Km hexokinase activity, which could contribute to a very fine regulation of their hexose metabolism. This strict regulation could ultimately be very important in optimizing dog-sperm function along its life-time.
authors.affiliation: Department of Biochemistry and Molecular Biology and IRBB, Barcelona Science Park, University of Barcelona, E-08028 Barcelona, Spain.
authors.forename: Josep M
authors.initials: JM
authors.lastname: Fernández-Novell
authors.forename: Joan
authors.initials: J
authors.lastname: Ballester
authors.forename: Antonio
authors.initials: A
authors.lastname: Medrano
authors.forename: Pedro J
authors.initials: PJ
authors.lastname: Otaegui
authors.forename: Teresa
authors.initials: T
authors.lastname: Rigau
authors.forename: Joan J
authors.initials: JJ
authors.lastname: Guinovart
authors.forename: Joan E
authors.initials: JE
authors.lastname: Rodríguez-Gil
mesh_terms: D000177:Acrosome / Q000378:metabolism; D000595:Amino Acid Sequence; D000818:Animals; D015153:Blotting, Western; D002352:Carrier Proteins / Q000378:metabolism; D004285:Dogs; D004305:Dose-Response Relationship, Drug; D015971:Gene Expression Regulation, Enzymologic; D006593:Hexokinase / Q000737:chemistry*; D007150:Immunohistochemistry; D047908:Intracellular Signaling Peptides and Proteins; D007700:Kinetics; D008099:Liver / Q000378:metabolism; D008297:Male; D018613:Microscopy, Confocal; D008969:Molecular Sequence Data; D051381:Rats; D013094:Spermatozoa / Q000378:metabolism*; D013552:Swine
chemical_list: D002352:Carrier Proteins; C499484:Gckr protein, rat; D047908:Intracellular Signaling Peptides and Proteins; C080906:glucokinase regulatory protein; D006593:Hexokinase