Oocyte-specific protein tyrosine kinase that phosphorylates and inhibits CDK1 and acts as a key regulator of meiosis during both prophase I and metaphase II. Required to maintain meiotic arrest in oocytes during the germinal vesicle (GV) stage, a long period of quiescence at dictyate prophase I, by phosphorylating CDK1 at 'Tyr-15', leading to inhibit CDK1 activity and prevent meiotic reentry. Also required for metaphase II exit during egg activation by phosphorylating CDK1 at 'Tyr-15', to ensure exit from meiosis in oocytes and promote pronuclear formation (By similarity). ATP + L-tyrosyl-[protein] = ADP + H(+) + O-phospho-L-tyrosyl-[protein] Phosphorylation leads to increase its activity. Belongs to the protein kinase superfamily. Ser/Thr protein kinase family. WEE1 subfamily.