کد مقاله | کد نشریه | سال انتشار | مقاله انگلیسی | نسخه تمام متن |
---|---|---|---|---|
10820440 | 1060649 | 2011 | 7 صفحه PDF | دانلود رایگان |
عنوان انگلیسی مقاله ISI
Phenoloxidase activity of intact and chemically modified functional unit RvH1-a from molluscan Rapana venosa hemocyanin
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کلمات کلیدی
VmaxHCsRVHHVHTyrosinase - تیروزیناز Michaelis–Menten constant - دائمی Michaelis-MentenMelting Temperature - دمای ذوبcircular dichroism - رنگ تابی دورانیEnzyme activation - فعال سازی آنزیمPhenoloxidase activity - فعالیت فنلوکسیدازPhenoloxidases - فنلوکسیدازHemocyanins - هموسیانین هاfunctional unit - واحد عملکردیpos - پست
موضوعات مرتبط
علوم زیستی و بیوفناوری
بیوشیمی، ژنتیک و زیست شناسی مولکولی
زیست شیمی
پیش نمایش صفحه اول مقاله
چکیده انگلیسی
o-Diphenol oxidase activities (o-diPO) of chemically modified functional unit RvH1-a of molluscan hemocyanin Rapana venosa were studied using L-Dopa and dopamine as substrates. With L-Dopa as substrate the native FU RvH1-a did not show any o-diPO activity. Therefore the native FU RvH1-a was converted to enzymatic active form, after treatment with SDS, trypsin, urea and different values of pH when its o-diPO activity was studied. The highest artificial induction of o-diPO activity was observed after incubation of FU with 3.0Â mM SDS, and RvH1-a shows both, dopamine (KMÂ =Â 6.53Â mM, kcat/KMÂ =Â 1.29) and L-Dopa (KMÂ =Â 2.0Â mM, kcat/KMÂ =Â 2.1) activity due to a more open active site of the enzyme and better access of the substrates. It was determined that the KM value of SDS-activated RvH1-a against dopamine is higher compared to those of hemocyanins from Helix vulgaris, Helix pomatia and native tyrosinase from Ipomoea batatas but much lower than that from Illex argentinus (ST94) tyrosinase and arthropodan hemocyanin from Carcinus aestuarii. The Km value of SDS-activated RvH1-a against L-Dopa is higher than those of hemocyanins from H. vulgaris and Cancer magister, but lower than that of the tyrosinase from Streptomyces albus.
ناشر
Database: Elsevier - ScienceDirect (ساینس دایرکت)
Journal: Comparative Biochemistry and Physiology Part B: Biochemistry and Molecular Biology - Volume 160, Issue 1, September 2011, Pages 1-7
Journal: Comparative Biochemistry and Physiology Part B: Biochemistry and Molecular Biology - Volume 160, Issue 1, September 2011, Pages 1-7
نویسندگان
Aleksandar Dolashki, Wolfgang Voelter, Pavlina Dolashka,