Figure 1.

The hypocretins are novel, secretin-related peptides. (A) Hypocretin rat/mouse nucleotide (coding region only) and amino acid sequences. Differences in nucleotide sequences are indicated by asterisks below each different base, amino acid differences are indicated above triplets. Tandem basic amino acids (putative sites for proteolytic maturation) are indicated in bold, as is the serine residue most likely to represent the end of the secretion signal. (B) Alignment of Hcrt1 and Hcrt2 with rat secretin. The first nine residues of secretin have been repeated to indicate apparent circular permutation. The identities between the hypocretins and members of the glucagon/vasoactive intestinal polypeptide/secretin family (3) are indicated by asterisks, the Hcrt1/2 consensus residues appear above the alignment. The complete rat and mouse sequences were obtained by standard methods.