Fig. 1.

Amino acid sequences of tryptic peptides released from the 122 kDa clock-stimulated phosphoprotein. The soluble fraction of homogenates of Limulus lateral optic nerves was fractionated by SDS-PAGE and blotted to nitrocellulose. The blot was stained with Ponceau S, and the 122 kDa band was cut out and digested with trypsin. Tryptic peptides were purified by HPLC; four were sequenced at the Microchemistry Department at Harvard University (Cambridge, MA) according to their standard procedures.