Table 1.

Quantification of N⁶-formyl-lysine in histone and other proteins

Identity and source of protein	N6-formyl-lysines per 104 lysines
Acid soluble protein from TK6 nuclei	9.1 ± 2.6
Calf thymus total histone*	7.7 ± 0.9
Chicken blood total histone†	11 ± 0.5
Acid soluble protein from TK6 cells	4.2 ± 1.5
Total protein from TK6 nuclei	12 ± 3
Proteinase K (4% lys)‡	<0.2
Bovine serum albumin (10% lys)	<0.2
Human collagen (5% lys)	<0.2
Human IgG (6% lys)	<0.2

*Acid-soluble protein containing all histone classes.

^†Acid-soluble/TCA-precipitated proteins from erythrocytes.

^‡Lysine content as mol percent of total amino acids.