8. Hydrolytic driving force. The hydrolysis of pyrophosphate to orthophosphate is important in driving forward biosynthe
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- 8 Hydrolytic Driving Force The Hydrolysis Of Pyrophosphate To Orthophosphate Is Important In Driving Forward Biosynthe 1 (224.88 KiB) Viewed 44 times
8. Hydrolytic driving force. The hydrolysis of pyrophosphate to orthophosphate is important in driving forward biosynthetic reactions such as the synthesis of DNA. This hydrolytic reaction is catalyzed in Escherichia coli by a pyrophosphatase that has a mass of 120kDa and consists of six identical subunits. For this enzyme, a unit of activity is defined as the amount of enzyme that hydrolyzes 10μmol of pyrophosphate in 15 minutes at 37∘C under standard assay conditions. The purified enzyme has a Vmax of 2800 units per milligram of enzyme. ✓4 a. How many moles of substrate are hydrolyzed per second per 530 milligram of enzyme when the substrate concentration is much greater than KM ? b. How many moles of active sites are there in 1mg of enzyme? Assume that each subunit has one active site. c. What is the turnover number of the enzyme? Compare this value with others mentioned in this chapter.