Biochemical composition of washed human seminal coagulum in comparison to sperm-free semen from the same donors.

Intra-individual inter-ejaculate variations in the amounts of protein, fructose, N-acetylamino sugar, phosphate, sialic acid and amino sugar in washed coagulum from normal ejaculates of men were highly consistent (N = 9). All the prostatic components studied (acid phosphatase, zinc, calcium and citric acid), except zinc, in the washed coagulum were reduced by 90% of their values in semen (N = 5). The seminal vesicular markers (fructose, N-acetylamino sugar and phosphate) had no association with the coagulum structure and represented the soluble components (N = 5). The concentrations of protein and zinc in the coagulum were higher than those of semen by 114% and 32% respectively. The coagulum contained sialic acid and amino sugar as integrated components.