کد مقاله | کد نشریه | سال انتشار | مقاله انگلیسی | نسخه تمام متن |
---|---|---|---|---|
10582825 | 981117 | 2005 | 18 صفحه PDF | دانلود رایگان |
عنوان انگلیسی مقاله ISI
The importance of the amide bond nearest the thiol group in enzymatic reactions of coenzyme A
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موضوعات مرتبط
مهندسی و علوم پایه
شیمی
شیمی آلی
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چکیده انگلیسی
Analogues of coenzyme A (CoA) and of CoA thioesters have been prepared in which the amide bond nearest the thiol group has been modified. An analogue of acetyl-CoA in which this amide bond is replaced with an ester linkage was a good substrate for the enzymes carnitine acetyltransferase, chloramphenicol acetyltransferase, and citrate synthase, with Km values 2- to 8-fold higher than those of acetyl-CoA and Vmax values from 14 to >80% those of the natural substrate. An analogue in which an extra methylene group was inserted between the amide bond and the thiol group showed less than 4-fold diminished binding to the three enzymes but exhibited less than 1% activity relative to acetyl-CoA with carnitine acetyltransferase and no measurable activity with the other two enzymes. Analogues of several CoA thioesters in which the amide bond was replaced with a hemithioacetal linkage exhibited no measurable activity with the appropriate enzymes. The results indicate that some aspects of the amide bond and proper distance between this amide and the thiol/thioester moiety are critical for activity of CoA ester-utilizing enzymes.
ناشر
Database: Elsevier - ScienceDirect (ساینس دایرکت)
Journal: Bioorganic Chemistry - Volume 33, Issue 2, April 2005, Pages 90-107
Journal: Bioorganic Chemistry - Volume 33, Issue 2, April 2005, Pages 90-107
نویسندگان
Jin Xun, Haidong Huang, Kurt W. Vogel, Dale G. Drueckhammer,