کد مقاله کد نشریه سال انتشار مقاله انگلیسی نسخه تمام متن
5202924 1381913 2011 9 صفحه PDF دانلود رایگان
عنوان انگلیسی مقاله ISI
Purification and characterization of an extracellular medium-chain length polyhydroxyalkanoate depolymerase from Thermus thermophilus HB8
موضوعات مرتبط
مهندسی و علوم پایه شیمی شیمی آلی
پیش نمایش صفحه اول مقاله
Purification and characterization of an extracellular medium-chain length polyhydroxyalkanoate depolymerase from Thermus thermophilus HB8
چکیده انگلیسی
During growth on medium-chain length (mcl) polyhydroxyalkanoates (PHAs), or on sodium octanoate Thermus thermophilus HB8 produces an extracellular mcl-PHA depolymerase. This enzyme was purified from the culture medium of sodium octanoate-grown cells to electrophoretic homogeneity by hydrophobic interaction chromatography using Octyl-Sepharose CL-4B and gel permeation chromatography using Sephadex G-150. The molecular mass of the purified enzyme was approximately 28 kDa. A part of the gene TTHA1605 encoding a 24.17 kDa protein was demonstrated to encode the mcl-PHA depolymerase of T. thermophilus. The primary amino-acid sequence of purified enzyme reveals similarity to all reported so far extracellular mcl-PHA depolymerases. The purified enzyme could hydrolyze mcl - PHAs and p-nitrophenyl (pNP) esters but not short chain length (scl) - PHAs. The optimum pH range was 7.5-9 and the optimum temperature was 70 °C for pNP-octanoate (pNPO) hydrolysis. The Km value for pNPO was 53.2 μM. The enzyme was strongly inhibited by phenylmethylsulfonyl fluoride (PMSF) and non-ionic detergents (Tween 20, Tween 80 and Triton X-100). The results demonstrated in this study revealed that the mcl-PHA depolymerase from T. thermophilus is a distinct enzyme, which is different from those of other mcl-PHA-degrading bacteria.
ناشر
Database: Elsevier - ScienceDirect (ساینس دایرکت)
Journal: Polymer Degradation and Stability - Volume 96, Issue 4, April 2011, Pages 670-678
نویسندگان
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