Current time in Korea 23:36 Jun 25 (Tue) Year 2019 KCS KCS Publications
KCS Publications
My Journal Log In Register
HOME > Search > Browsing(JKCS) > Archives

Journal of the Korean Chemical Society (JKCS)

ISSN 1017-2548(Print)
ISSN 2234-8530(Online)
Volume 33, Number 1
JKCSEZ 33(1)
February 20, 1989 

 
Title
A Study on the Hydrolysis of p-Nitrophenyl Carboxylates by Micellar Surfactants Catalysts Involving Histidyl Residue

히스티딜기등을 포함하는 미셀성 계면활성제를 촉매로 사용한 파라니트로페닐 에스테르의 가수분해반응에 관한 연구
Author
Won Fae Koo, Choon Pyo Hong

구원회, 홍춘표
Keywords
Abstract
파파인효소의 가수분해반응을 이해하기 위하여 파파인의 활성점에 모여 있는 히스티딘, 시스테인, 및 히스테인-시스테인을 포함하는 양이온성 펩티드-계면활성제를 합성하였다. 이것을 촉매로 사용하여 PNPL을 가수분해 시킬때 pH 7.40에서 촉매의 효율성은 N+C2AlaC12과 비교하여 N+C2CysC12, N+C2HisC12, N+C2HisCysC12 순으로 현저한 증가를 나타내고 그 이유는 N+C2HisC12는 이미다졸기, N+C2CysC12는 티올기 영향이며, 가장 좋은 촉매효율을 나타내는 N+C2HisCysC12은 이미다졸기와 티올기의 상호작용때문이다. 가수분해반응을 촉진시키는 펩티드-계면활성제의 이미다졸기와 티올기들의 활동성을 나타내는 해리상수, pKa는 각각 6.49, 10.50 이고, 기능기에 의한 속도상수, km*는 각각 7.91 × l0-4 S-1, 6.00 × 10-4S-1이었다. 가수분해에 대한 혼합미셀계의 촉매효과는 파라니트로페닐 에스테르의 알킬기의 탄소수가 증가함에 따라 증가하므로 기능기의 작용외에는 미셀의 소수성 부분과 기질사이의 상호작용에 의하여도 증가됨을 알았다.

In order to obtain a clue in understanding enzymatic hydrolysis in which the His-Cys moieties of papain protease is involved, we prepared cationic peptide-sufactants bearing histidyl, cysteinyl, and both histydyl and cysteinyl residues. Their catalytic efficiency toward the hydrolysis of PNPL were investigated in comicellar phases formed with N+C2CysC12, N+C2HisC12, N+C2HisCysC12 increased markedly in the same order compared with that of N+C2AlaC12. The markedly increased catalytic effects are attributed to the imidazole groups of N+C2HisC12 and the thiol groups of N+C2CysC12, and the large catalytic efficiency of N+C2HisCysC12, is considered due to the interaction of the imidazole and the thiol groups. In order to investigate catalytic activities, rate constants for the functional groups, km* and dissociation constants, pKa have been determined. The results showed that km* and pKa of the imidazole groups were 7.91 × l0-4 S-1 and 6.49, and those of the thiol groups were 6.00 × 10-4S-1 and 10.50. The catalytic effects of comicellar systems on the hydrolysis of p-nitrophenyl esters has increased according to the increasing size of the alkyl carbon number. Therefore, the catalytic effects have been increasing by the interaction of micellar hydrophobic parts and substrates as well as action of the functional groups.

Page
3 - 10
Full Text
PDF