Authors: Ahmed K A ElSayed Mohamed I Abou Dobara Amira A ElFallal Noha F Omar
Publish Date: 2013/04/04
Volume: 170, Issue: 3, Pages: 483-497
Abstract
αAmylase from Thermoactinomyces vulgaris was highly purified 489fold by ammonium sulfate precipitation gel filtration on Sephadex G50 column and ion exchange chromatography column of DEAEcellulose The molecular weight of the enzyme was estimated to be 135 and 145 kDa by SDS–PAGE Its high molecular weight is due to high glycosylation The purified amylase exhibited maximal activity at pH 60 to 70 and was stable in the range of pH 40 to 90 The optimum temperature for its activity was 50 °C The enzyme halflife time was 120 min at 50 °C suggesting intermediate temperature stable αamylase The enzyme was sensitive to different metal ions including NaCl CoCl2 and CaCl2 and to different concentrations of EDTA The enzyme activity was inhibited in the presence of 1 mM CaCl2 suggesting that it is a calciumindependent αamylase The TLC showed that the amylase hydrolyzed starch to produce large maltooligosaccharides as the main products A 11kb DNA fragment of the putative αamylase gene amy TVE from T vulgaris was amplified by using two specific newly designed primers Sequencing analysis showed 562 similarity to other Thermoactinomyces αamylases with two conserved active sites confirming its function
Keywords: