N-Terminal acetyl-peptides from two calf thymus histones.

1. The same N-terminal peptide was isolated from two major calf thymus histone fractions, F2al and F2a2. 2. The structure of the peptides is N-acetylseryl-glycyl-arginine, and the yields account for most of the N-acetyl groups previously found in these histones. 3. Some other peptides not giving a ninhydrin reaction were also investigated.