Facile solid-phase synthesis of sulfated tyrosine-containing peptides: Part II. Total synthesis of human big gastrin-II and its C-terminal glycine-extended peptide (G34-Gly sulfate) by the solid-phase segment condensation approach.
Application of the fluoren-9-ylmethoxycarbonyl (Fmoc)-based solid-phase segment condensation approach to the preparation of sulfated peptides was investigated through the synthesis of human big gastrin-II, a 34-residue sulfated tyrosine [Tyr(SO3H)]-containing peptide. Highly acid-sensitive 2-chlorotrityl resin (Clt resin) was exclusively employed as an anchor-resin for the preparation of the three peptide segments having the C-terminal Pro residue as well as of the Tyr(SO3H)-containing resin-bound segment. By using the PyBOP-mediated coupling protocol [PyBOP=benzotriazolyloxytris(pyrrolidino)phosphonium hexafluorophosphatel, we successively condensed each segment and constructed the 34-residue peptide-resin without any difficulty. The final acid treatment of the fully protected peptide-resin at low temperature (90% aqueous TFA, 0 degree C for 8 h), which can detach a Tyr(SO3H)-containing peptide from the resin and remove the protecting groups concurrently with minimum deterioration of the sulfate, afforded a crude sulfated peptide. After one-step HPLC purification, a highly homogeneous human big gastrin-II was easily obtained in 14% yield from the protected peptide-resin. The sulfate form of the C-terminal glycine-extended gastrin (G34-Gly sulfate), a posttranslational processing intermediate of gastrin-II, was also successfully prepared with the segment condensation approach (11% yield). These results demonstrated the usefulness of the segment condensation protocol for preparing large Tyr(SO3H)-containing peptides.
Kitagawa
K
K
Niigata College of Pharmacy, Japan. kouki@niigata-pharm.ac.jp
Aida
C
C
Fujiwara
H
H
Yagami
T
T
Futaki
S
S
D005755:Gastrins / Q000138:chemical synthesis*; D005998:Glycine / Q000138:chemical synthesis*; D006801:Humans; D010455:Peptides / Q000138:chemical synthesis*; D011498:Protein Precursors / Q000138:chemical synthesis*; D011499:Protein Processing, Post-Translational; D013431:Sulfates / Q000138:chemical synthesis*; D014443:Tyrosine / Q000138:chemical synthesis*
D005755:Gastrins; D010455:Peptides; D011498:Protein Precursors; D013431:Sulfates; C058638:tyrosyl-glycyl-tryptophyl-methionyl-aspartyl-phenylalanyl-glycine; C013706:big gastrin; D014443:Tyrosine; D005998:Glycine