“Since some mitogenic hormones stimulate a tyrosine-specific protein kinase activity, and since the transforming protein of RSV is a tyrosine-specific protein kinase, we have examined whether TPA also stimulates protein phosphorylation on tyrosine.”
“We report here that TPA treatment of normal cells resulted in a very rapid phosphorylation on tyrosine of a protein peak of Mr 40 to 43 kilodaltons.”