衍生自人ⅡA型磷脂酶A_2碳末端的多肽C-26杀菌作用研究

Study on Bactericidal Activity of the Polypeptide C-26 Derived from C-terminal of Human Group ⅡA Phospholipase A_2

目的:考察衍生自人ⅡA型磷脂酶A(2ⅡA型PLA2)碳(C)末端的多肽C-26对不同细菌的体外杀菌作用。方法:根据人ⅡA型PLA2C末端26个氨基酸残基的顺序,合成多肽C-26。采用琼脂铺板计数法,将不同浓度的多肽C-26分别与6种细菌(金黄色葡萄球菌、炭疽杆菌、枯草杆菌、大肠杆菌、变形杆菌和绿脓杆菌)在37℃孵育2h,然后铺板并置于37℃恒温箱培养18～24h,记录每一琼脂板上的菌落形成单位(cfu),计算出多肽C-26作用后对细菌的杀菌率。结果:多肽C-26对金黄色葡萄球菌、枯草杆菌、炭疽杆菌等革兰阳性(G+)细菌的杀菌作用较强,其杀灭99%细菌的浓度在250～1000mg·L-1之间;对大肠杆菌、变形杆菌、绿脓杆菌等革兰阴性(G-)细菌的杀菌作用较弱,其浓度在500mg·L-1时对三者的杀菌率为41%～52%。结论:多肽C-26有杀菌作用,推测其具有与ⅡA型PLA2及其他抗菌多肽相似的杀菌机制。

OBJECTIVE： To observe the bactericidal activity of the polypeptide C-26 which derives from C-terminal of human group ⅡA phospholipase A2（group ⅡA PLA2）.METHODS： According to C-terminal 26 amino acid residues sequence of human group ⅡA phospholipase A2,a piece of polypeptide C-26 had been synthesized.6 kinds of bacterial strains （Staphylococcus aureus,Bacillus subtilis,Bacillus anthrax,Escherichia coli,Bacillus proteus and Bacillus pyocyaneus） were incubated with different concentration of polypeptide C-26 at 37 ℃ for 2 h in a water bath respectively.After incubated for 18～24 hours in the thermostated container at 37 ℃,the colony formed unit was counted and the bactericidal rates of polypeptide C-26 were calculated.RESULTS： The polypeptide C-26 possessed potent bactericidal activity to the gram-positive（G＋） bacteria,such as Staphylococcus aureus,Bacillus subtilis,Bacillus anthrax,the concentration of polypeptide C-26 against 99% bacteria ranged 250～1 000 mg·L-1;it possessed weak bactericidal activity to the gram-negative （G-） bacteria,such as Escherichia coli,Bacillus proteus,Bacillus pyocyaneus.The bactericidal rate of polypeptide C-26 with the concentration of 500 mg·L-1 were 41%～52%.CONCLUSION： The polypeptide C-26 which derives from C-terminal of human group ⅡA PLA2 possesses bactericidal activity,it is speculated that the polypeptide might have similar bactericidal mechanism as human group ⅡA PLA2 and the other antibacterial peptides.