Figure 1 - Time course of protein (filled circles) and amino acid (filled squares) release by proteolytic treatments. The figure presents data for trypsin-treated normozoospermic samples as a typical pattern of peptide release. Sperm (90 x 106) were incubated at 37oC in PBS containing 0.8 mg/ml trypsin for different times. Assays for amino acids/low molecular weight peptides, and proteins were carried out by the ninhydrin and Lowry methods, as described in Material and Methods.