PRESENCE AND CHEMICAL-COMPOSITION OF GLYCOPROTEIC LAYER ON HUMAN SPERMATOZOA

Studies from electronic microscopy disclosed the presence of an electr odense stranded and branchlike electrodense layer that extends toward extracellular space. Chemical composition of this glycoproteic layer s howed that protein and total sugar content is similar (0.98 mu g/mu g protein). As for the total sugar content of this glycoproteic constitu ent, sialic acid accounts for 40%, hexosamines 27%, and fucose 30%. El ectrophoresis characterization of this constituent showed the presence of 6 different motility bands. Risen levels of sialic acid indicate t he contribution of sialic residue in the net charge of the sperm membr ane, its role during capacitation, and its possible participation in t he formation of binding bridges between sperm membrane and ovum.