Table 1.

In vitro kinase substrates for 354 wild-type human protein kinases.

	Number of phosphositesa
	pS/T/Y	pS	pT	pY
All kinases	175,574	59,945	26,724	88,905
STKs	83,018	54,945	23,160	4,913
TKs	92,556	5,000	3,564	83,992
Unique phosphosites	20,669	9,998	4,698	5,973

^aThe phosphosites were obtained from identified phosphopeptides that satisfied quantitative criteria, i.e., a peak area ratio of more than 2.