Synthesis and biological activity of seleno sunflower trypsin inhibitor analog.

Xin Guo, Jiahao Shi, Zhenyu Tang, Dafu Cui, Youshang Zhang

Institute of Protein Research , Tongji University, Shanghai, China.

Chemical biology & drug design 2006 Dec

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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.

Citation

Xin Guo, Jiahao Shi, Zhenyu Tang, Dafu Cui, Youshang Zhang. Synthesis and biological activity of seleno sunflower trypsin inhibitor analog. Chemical biology & drug design. 2006 Dec;68(6):341-4