title: Conformation and biological studies of synthesized Trp4-Met5 enkephalin N-protected with 3,5-dimethoxy-alpha, alpha-dimethylbenzoylcarbonyl group.
abstract: A highly purified Trp4-Met5 enkephalin was synthesized using liquid phase method of peptide synthesis. Polyethylene glycol (PEG) ans 3,5-dimethoxy-alpha, alpha-dimethylbenzoylcarbonyl group (Ddz) were used as blocking groups for C- and N-terminals, respectively. Ddz group proved to be the suitable N-protecting group for tryptophan-containing peptide. Its acid sensitivity permits mild cleavage without damage to tryptophan. Attachment of methionine with PEG was catalyzed by 18-crown-6. This raised the yield of incorporation from 36 to 98%. Morphine like activity of the prepared peptide was tested by injection into the lateral brain ventricle of the rat. It has a highly biological potency. Conformational studies in solution by CD, energy transfer and in solid state by IR spectroscopy indicated that Trp4-Met5 enkephalin adopts a beta-turn conformation. The intramolecular distance between Tyr and Trp was 11.6 A.
authors.affiliation: Department of Chemistry, Faculty of Science, Zagazig University, A.R.E.
authors.forename: S
authors.initials: S
authors.lastname: Abdel Rahman
authors.forename: A
authors.initials: A
authors.lastname: Hattaba
mesh_terms: D000700:Analgesics / Q000032:analysis / Q000138:chemical synthesis*; D000818:Animals; D002942:Circular Dichroism; D004744:Enkephalin, Methionine / Q000031:analogs & derivatives* / Q000032:analysis / Q000138:chemical synthesis; D008297:Male; D009043:Motor Activity / Q000187:drug effects; D011487:Protein Conformation; D051381:Rats; D013050:Spectrometry, Fluorescence; D013055:Spectrophotometry, Infrared
chemical_list: D000700:Analgesics; D004744:Enkephalin, Methionine; C056553:enkephalin-Met, Trp(4)-