Metabolic labeling of mitogen-activated protein kinase kinase in A431 cells demonstrates phosphorylation on serine and threonine residues.
Ahn NG, Campbell JS, Seger R, Jensen AL, Graves LM, Krebs EG. Metabolic labeling of mitogen-activated protein kinase kinase in A431 cells demonstrates phosphorylation on serine and threonine residues. Proc Natl Acad Sci U S A. 1993 Jun 01; 90(11):5143-7.