AMINO-ACID-SEQUENCE OF THE MINOR ISOMORPH OF THE CRUSTACEAN HYPERGLYCEMIC HORMONE (CHH-II) OF THE MEXICAN CRAYFISH PROCAMBARUS-BOUVIERI (ORTMANN) - PRESENCE OF A D-AMINO-ACID
Mb. Aguilar et al., AMINO-ACID-SEQUENCE OF THE MINOR ISOMORPH OF THE CRUSTACEAN HYPERGLYCEMIC HORMONE (CHH-II) OF THE MEXICAN CRAYFISH PROCAMBARUS-BOUVIERI (ORTMANN) - PRESENCE OF A D-AMINO-ACID, Peptides, 16(8), 1995, pp. 1375-1383
The primary structure of the neurohormone crustacean hyperglycemic hor
mone (CHH-II) was determined by means of enzymatic digestions, manual
Edman degradation, and mass spectrometry. CHH-II is a 72 residue pepti
de (molecular mass 8388 Dal, with six cysteines forming three disulfid
e bridges that connect residues 7-43, 23-39, and 26-52. The peptide ha
s bloc):ed N- and C-termini, and lacks tryptophan, histidine, and meth
ionine. The CHH-I and CHH-II of Procambarus bouvieri have identical se
quences and elicit levels of hyperglycemia that are not distinguishabl
e. The difference between the two isomorphs consists in a posttranslat
ional modifcation of a L-Phe in CHH-I to a D-Phe in CHH-II at the thir
d position from the N-terminus.