Fig. 8. Wild-type and GalT I-null sperm show similar profiles of capacitation-dependent protein tyrosine phosphorylation. Wild-type (gt +/+) and GalT I-null (gt –/–) sperm lysates were fractionated by SDS-PAGE, transferred to nitrocellulose and probed with anti-phosphotyrosine and anti--tubulin antibodies. The arrow indicates a protein of 200 kDa that is present only in GalT I-null sperm lysates. This blot is representative of at least six experiments. (C) Protein kinase A activity in wild-type (gt +/+) and GalT I-null (gt –/–) sperm capacitated for varying periods of time in HCO₃^– -containing or HCO₃^– -free media. Each point represents the mean±standard error; n=3 experiments. In a single experiment, the value of each data point represents three determinations. Thus, each data point reflects data collected from nine assays.