This amino acid in photosystem II receives the electrons freed by hydrolysis, passing them onto P680. (-5[1])This (10[1])amino acid is phosphorylated by a mythically named enzyme that activates STAT (stat) transcription factors. Epidermal growth factor causes formation of a membrane-bound (10[1])dimer (DIE-mur) that phosphorylates this amino acid. Protein kinases are specific to either serine and threonine (THREE-ah-neen), or to (10[1]-5[1])this amino acid. The breakdown of casein (KAY-seen) can form white crystals of this amino acid, whose name comes from the Greek for ■END■