Levitide is a neurohormone-like peptide, can be isolated from skin secretions of the South African frog Xenopus laevis. Levitide comes from preprolevitide, is 88 residues long and contains contains the levitide peptide at the C terminus (Glu-Gly-Met-Ile-Gly-Thr-Leu-Thr-Ser-Lys-Arg-Ile-Lys-Gln-NH2) and the putative signal sequence at the N terminus.

Neuropeptide Y (1-24) (human) is a neuropeptide with potencies in inhibiting the electricity stimulated twitch response of rat vas deferens. Neuropeptide Y (1-24) (human) stimulates N-methyl-D-aspartate (NMDA)-induced neuronal activation in the rat CA3 region of the dorsal hippocampus in vivo.

Thiamet G is a potent, selective O-GlcNAcase inhibitor with Kiof 21 nM, while exhibiting 37, 000-fold selectivity over human lysosomal –hexosaminidase.