The subfamily of class B secretin-like receptors includes approximately 30 different receptors for a variety of peptide hormones and neuropeptides. Family B receptors are characterized by a long amino terminus (~ 100 residues) containing several cysteines that presumably form a network of disulfide bridges. Similar to the A receptors, the B receptors contain a disulfide bridge connecting the second EL and third EL. However, the palmitoylation site is missing. Moreover, the conserved prolines in the B receptors are different from the conserved prolines in the A receptors, and the DRY motif at the TM3 is absent.

Ref. Gether, U. Endocrine Reviews 2000, 21, 90–113; Harmar, A. J. Genome Biology 2001, 2, 3013–3013