label: RNA polymerase II CTD heptapeptide repeat Y1 kinase activity
label_lc: rna polymerase ii ctd heptapeptide repeat y1 kinase activity
description: "Catalysis of the reaction: ATP + RNA polymerase II large subunit CTD heptapeptide repeat (consensus YSPTSPS) = ADP + H+ + RNA polymerase II large subunit phosphotyrosine (position 1)."