N-terminal amino acid sequence of an insect neurohormone, melanization and reddish coloration hormone (MRCH): heterogeneity and sequence homology with human insulin-like growth factor II.

An insect neurohormone, melanization and reddish coloration hormone (MRCH), is responsible for cuticular melanization and epidermal red pigmentation in the armyworm. The three molecular forms of MRCH were isolated from adult heads of the silkworm, Bombyx mori, and their N-terminal amino acid sequences revealed a sequence homology with the C-terminal region of human insulin-like growth factor-II as well as N-terminal heterogeneity of MRCHs.