Single-step purification of two hyperglycaemic neurohormones from the sinus gland of Procambarus bouvieri. Comparative peptide mapping by means of high-performance liquid chromatography.

A crude aqueous extract from 2000 sinus glands of the Mexican crayfish Procambarus bouvieri (Ortmann) was fractionated on a muBondapak-Phenyl column. Two isoforms of the crustacean hyperglycaemic hormone, designated CHH-B and CHH-C in order of elution, were isolated in pure form. Their biochemical characterization showed a remarkable degree of homology. A tryptic digest of each isohormone was fractionated on an Ultrasphere-ODS column. Only one tryptic peptide in CHH-C was eluted later than its homologous peptide in CHH-B. On acid hydrolysis both tryptic peptides had the same composition but, as they contain Asp and Glu, we suspect that the difference residues in a double reciprocal amidation-deamidation of two acidic residues.