Effects of protein tyrosine kinase inhibitors on egg activation and fertilization-dependent protein tyrosine kinase activity

Analysis of the influence of protein tyrosine kinase inhibitors such as genistein on fertilized sea urchin eggs reveals that genistein curbs phosphorylation of a 350 KDa protein and fertilization-mediated activity of protein kinase. At concentrations of above 100 micromoles, protein kinase C activity is disrupted, as also DNA synthesis and cell division.