کد مقاله | کد نشریه | سال انتشار | مقاله انگلیسی | نسخه تمام متن |
---|---|---|---|---|
7622927 | 1494540 | 2016 | 13 صفحه PDF | دانلود رایگان |
عنوان انگلیسی مقاله ISI
3 or 3â²-Galloyl substitution plays an important role in association of catechins and theaflavins with porcine pancreatic α-amylase: The kinetics of inhibition of α-amylase by tea polyphenols
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کلمات کلیدی
GTEOTETf2KmappKICPPATESepicatechinEGCGepigallocatechinEGCtf1 - TF1α-Amylase - α-آمیلازporcine pancreatic α-amylase - α-آمیلاز پانکراس خوکیTannic acid - اسید تانیکECG - الکتروکاردیوگرام یا نوار قلبepicatechin gallate - اپیکتچین گالاتepigallocatechin gallate - اپی گالوستاچین گالاتInhibition - بازداریTheaflavin - تئوفلاوینKinetics - سینتیک (جنبش شناسی) Tea extracts - عصاره چایGreen tea extracts - عصاره چای سبزBTE - وسایل کمکTea polyphenols - پلی فنل چایKIU - چیCatechin - کاتچین، کتیچینCaffeine - کافئینGallic acid - گالیک اسید
موضوعات مرتبط
مهندسی و علوم پایه
شیمی
شیمی آنالیزی یا شیمی تجزیه
پیش نمایش صفحه اول مقاله
چکیده انگلیسی
The inhibitory activities of three tea extracts (TEs) and individual phenolic compounds in TEs against porcine pancreatic α-amylase (PPA) were studied by measuring their half inhibitory (IC50) concentrations. The kinetics of inhibition by these extracts and compounds were investigated through Dixon, Cornish-Bowden, and Lineweaver-Burk plots. The results showed that green, oolong and black tea extracts, epigallocatechin gallate, theaflavin-3, 3â²-digallate and tannic acid were competitive inhibitors of PPA, whereas epicatechin gallate, theaflavin-3â²-gallate and theaflavin were mixed-type inhibitors with both competitive and uncompetitive inhibitory characteristics. Only catechins with a galloyl substituent at the 3-position showed measurable inhibition. The competitive inhibition constants (Kic) were lower for theaflavins than catechins, with the lowest value for theaflavin-3, 3â²-digallate. The lower Kic than the uncompetitive inhibition constant for the mixed-type inhibitors suggests that they bind more tightly with free PPA than with the PPA-starch complex. A 3 and/or 3â²-galloyl moiety in catechin and theaflavin structures was consistently found to increase inhibition of PPA through enhanced association with the enzyme active site.
ناشر
Database: Elsevier - ScienceDirect (ساینس دایرکت)
Journal: Journal of Functional Foods - Volume 26, October 2016, Pages 144-156
Journal: Journal of Functional Foods - Volume 26, October 2016, Pages 144-156
نویسندگان
Lijun Sun, Fredrick J. Warren, Gabriele Netzel, Michael J. Gidley,