3 / 2021-09-18 20:52:11

Novel ACE inhibitory peptide isolated from Sipunculus nudus Linnaeus and its long-circulating preparation conjugated with DSPE-PEG

peptide；Sipunculus Linnaeus；long-circulating

ABSTRACT:

Objective In order to develop a long-circulating preparation of a peptide marine drug lead SRP, Polyethylene glycol tripeptide coupling (DSPE-PEG-SRP) was synthesized and characterized its physic and chemical properties.

Method   Raw material tripeptide SRP was modified at the N-terminal with DSPE-PEG-NHS by a nucleophilic substitution reaction to prepare the DSPE-PEG-SRP. The reaction conditions, including solvent, ratio, pH, and reaction time, were optimized systematically. The product was monitored by thin layer chromatography and characterized by SEM, FTIR, MADIL-TOF-MS.

Result In TLC assay, a new spot was found and it can be colored with ninhydrin solution, indicating a new peptide compound was synthesized. The product DSPE-PEG-SRP has characteristic absorption peaks at about 1686cm^-1 and 1468cm^-1 by FTIR, which are amide I band and amide II band, respectively. Therefore, SRP and DSPE-PEG-NHS are connected by an amide bond. SEM is used to observe the morphology of the product and raw material. The product connected with some small balls through bonds, while raw material DSPE-PEG-NHS is a loose structure. MADIL-TOF-MS showed that the molecular weight of the final product was consistent with the theoretical molecular weight of DSPE-PEG-SRP. Two monomers with molecular weights of 2550.056 Da and 3071.598Da were consistent with the theoretical molecular weights of DSPE-PEG-SRP obtained by DSPE-PEG-NHS with molecular weights of 2304.783 Da and 2828.033 Da, which confirmed that the product was the target compound DSPE-PEG-SRP.

Conclusion   A long-circulating antihypertensive preparation, DSPE-PEG-SRP, is synthesized, which has great application prospect in antihypertensive field.