کد مقاله | کد نشریه | سال انتشار | مقاله انگلیسی | نسخه تمام متن |
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1948046 | 1054672 | 2009 | 7 صفحه PDF | دانلود رایگان |
Purified trehalose-6-phosphate synthase (TPS) of Saccharomyces cerevisiae was effective over a wide range of substrates, although differing with regard to their relative activity. Polyanions heparin and chondroitin sulfate were seen to stimulate TPS activity, particularly when a pyrimidine glucose nucleotide like UDPG was used, rather than a purine glucose nucleotide like GDPG. A high Vmax and a low Km value of UDPG show its greater affinity with TPS than GDPG or TDPG. Among the glucosyl acceptors TPS showed maximum activity with G-6-P which was followed by M-6-P and F-6-P. Effect of heparin was also extended to the purification of TPS activity, as it helped to retain both stability and activity of the final purified enzyme. Metal co-factors, specifically MnCl2 and ZnCl2 acted as stimulators, while enzyme inhibitors had very little effect on TPS activity. Metal chelators like CDTA, EGTA stimulated enzyme activity by chelation of metal inhibitors. Temperature and pH optima of the purified enzyme were determined to be 40 °C and pH 8.5 respectively. Enzyme activity was stable at 0–40 °C and at alkaline pH.
Journal: Biochimica et Biophysica Acta (BBA) - General Subjects - Volume 1790, Issue 5, May 2009, Pages 368–374