Substitution of norleucine for methionine residues in a crustacean pigment-dispersing hormone

Peptides. 1985 May-Jun;6(3):491-4. doi: 10.1016/0196-9781(85)90115-9.


In order to evaluate the structural/functional roles of Met residues in an octadecapeptide pigment-dispersing hormone (PDH: Asn-Ser-Gly-Met-Ile-Asn-Ser-Ile-Leu-Gly-Ile-Pro-Arg-Val-Met-Thr-Glu-Ala- NH2), first described as light-adapting distal retinal pigment hormone (DRPH) from Pandalus, three analogs were synthesized: Nle4-PDH, Nle15-PDH, and Nle4,15-PDH. When tested for melanophore pigment-dispersing activity in destalked Uca, all three Nle-analogs were more potent than unsubstituted PDH. Performic acid oxidation caused a marked loss of potency of PDH, Nle4-PDH, and Nle15-PDH. The analog Nle4,15-PDH was resistant to oxidation and displayed 6-fold higher potency than PDH. Thus Met4 and Met15 are not essential for the PDH activity. The oxidation-induced loss of activity of unsubstituted PDH may result from introduction of oxygen (in methionine sulfone) and a consequent conformational change in the octadecapeptide.

Publication types

  • Research Support, U.S. Gov't, Non-P.H.S.

MeSH terms

  • Aminocaproates*
  • Animals
  • Crustacea / physiology
  • Insect Hormones / chemical synthesis*
  • Insect Hormones / pharmacology
  • Melanophores / drug effects
  • Methionine
  • Neurosecretory Systems / physiology
  • Norleucine*
  • Oxidation-Reduction
  • Peptides / chemical synthesis*
  • Peptides / pharmacology
  • Protein Conformation
  • Skin Pigmentation
  • Structure-Activity Relationship


  • Aminocaproates
  • Insect Hormones
  • Peptides
  • Norleucine
  • melanophore-dispersing hormone
  • Methionine