防御素研究进展

The advances in study of defensins

防御素是广泛分布于自然界中的广谱性抗菌多肽,在生物体内由特殊的细胞合成,经过一系列的加工后分泌表达出功能分子,由于其抗菌活性高,且作用范围广,引起了人们极大的兴趣,目前通过对其天然表达细胞的培养、合成肽和基因表达等手段制备,并进一步对其作用机理进行了探讨,但临床应用仍未见报道。

Defensins constitute a family of 3 - 4 kD antimicrobial peptides, and scattered widely in nature, including mammals, birds, amphibia, insects and plants. They are moderately cationic, nonglyco-sylated peptides. The defensins typically consists of 29-34 aa with a conserved pattern of disuifide linkage among its 6 cysteines. It is synthesized and stored as preproproteins in the cytoplasmic granules of neutrophils, some macrophages, and intestinal Paneth cells. Mutistep processing yields the mature pep-tides, which generally acts by inducing microbial membrane permeahilization. The microbicidal and cy-totoxic properties of defensins are most likely a consequence of their ability to insert into biological membranes and to generate pores. It is particular function in the initial phases to resistance microbial invasion. Some defensins are broadly antimicrobial, antiviral, and cytotoxic, while others are chemotac-tic. opsonic , or may modulate hormonal responses.