in the parent peptide , serine 115 was the initial site of phosphorylation but after prolonged phosphorylation other sites became phosphorylated ( serine 110 and/or serine 112 ) , further supporting the concept that arginine residues act as essential substrate specificity determinants for phospholipid/ca2+-dependent protein kinase .
C0031715
phosphorylation
C0033640
protein kinase