Table 1.

Proteins and the corresponding peptides identified in unlabeled protein extract (¹⁴N extract) and ¹⁵N labeled extract (¹⁵N extract) in two consecutive database searches without (¹⁴N search) and with (¹⁵N search) ¹⁵N as a fixed modification.

	Proteins		Peptides
	14N search	15N search	14N search	15N search
14N extract	195	1	536	2
15N extract	4	167	6	415