The presence of a high‐Km hexokinase activity in dog, but not in boar, sperm

• DOI: 10.1016/j.febslet.2004.06.015
• Publication Date: 2004-06-17T17:05:21Z
• Authors: Josep M Fernández...; Joan Ballester; Antonio Medrano; Pedro J Otaegui; Teresa Rigau; Joan J Guinovart; Joan E Rodrı́guez...
• Keywords: Male; Swine; Blotting, Western; Molecular Sequence Data; Gene Expression Regulation, Enzymologic; High-Km hexokinase; 03 medical and health sciences; Dogs; Hexokinase; Animals; Amino Acid Sequence; 0303 health sciences; Microscopy, Confocal; Dose-Response Relationship, Drug; Intracellular Signaling Peptides and Proteins; Immunohistochemistry; Spermatozoa; Rats; Glucokinase-regulatory protein; Dog-sperm; Kinetics; Liver; Glucokinase-regulatory; Carrier Proteins; Acrosome

The presence of a high‐K m 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‐K m 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.