title: Synthesis and biological activity of seleno sunflower trypsin inhibitor analog.
abstract: Sunflower trypsin inhibitor (SFTI-1) is a cyclic peptide with 14 amino acid residues and one disulfide bond. Its synthetic acyclic analog (aSFTI-1) with N-terminal Gly and C-terminal Asp was still active. Here, we report the synthesis of seleno aSFTI-1 with the disulfide bond of aSFTI-1 replaced by diselenide bond. The formation of the diselenide bond from selenol was achieved in a single step without the aid of oxidizing agent. For comparison, aSFTI-1 itself and aSFTI-1 with its disulfide bond replaced by two serines ([Ser(3,11)] aSFTI-1) were also synthesized. The trypsin inhibitory constants of seleno aSFTI-1, aSFTI-1 and [Ser(3,11)] aSFTI-1 were determined as 6.50 x 10(-9), 1.96 x 10(-9) and 8.10 x 10(-6) respectively, indicating that the disulfide bond is essential for the structure and function of aSFTI-1, and seleno aSFTI-1 is still active, although its inhibitory constant is reduced to 30% in comparison with that of aSFTI-1.
authors.affiliation: Institute of Protein Research , Tongji University, Shanghai, China.
authors.forename: Xin
authors.initials: X
authors.lastname: Guo
authors.forename: Jiahao
authors.initials: J
authors.lastname: Shi
authors.forename: Zhenyu
authors.initials: Z
authors.lastname: Tang
authors.forename: Dafu
authors.initials: D
authors.lastname: Cui
authors.forename: Youshang
authors.initials: Y
authors.lastname: Zhang
mesh_terms: D000595:Amino Acid Sequence; D008969:Molecular Sequence Data; D010455:Peptides / Q000138:chemical synthesis / Q000737:chemistry / Q000494:pharmacology; D010456:Peptides, Cyclic / Q000138:chemical synthesis / Q000737:chemistry* / Q000494:pharmacology*; D051140:Selenoproteins / Q000138:chemical synthesis / Q000737:chemistry* / Q000494:pharmacology*; D014357:Trypsin / Q000187:drug effects; D014361:Trypsin Inhibitors / Q000138:chemical synthesis / Q000737:chemistry* / Q000494:pharmacology*
chemical_list: D010455:Peptides; D010456:Peptides, Cyclic; D051140:Selenoproteins; D014361:Trypsin Inhibitors; C518078:acyclic sunflower trypsin inhibitor; C518080:acyclic sunflower trypsin inhibitor, Ser(3,11)-; C518079:seleno acyclic sunflower trypsin inhibitor; D014357:Trypsin