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E. Coli Phoa

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Characterization of enzyme kinetics can provide valuable insights into enzymatic reaction mechanisms. We are often interested in the effects of specific amino acid side chains on catalytic efficiency, or the efficiency of an enzyme with various substrates. In this experiment, we will determine some of the kinetic properties of alkaline phosphatase (PhoA or ALP), an enzyme that is found in nearly all organisms. E. coli PhoA is a periplasmic enzyme that hydrolyzes phosphate monoesters and has a high (alkaline) pH optimum. For this laboratory, we take advantage of the observation that PhoA hydrolyzes p-nitrophenylphosphate (PNPP, colorless) to give a colored product, p-nitrophenol. The progress of the reaction is assessed by monitoring formation …show more content…

It decreases the activation energy in reaction. When the substrate binds to the active site on enzyme, it will change the conformation of enzyme to make the enzyme-substrate complex and catalyze reactions2. The reason we want to analyze enzyme kinetic in order to quantitative biocatalysis, understand the catalytic mechanism and understand regulation of …show more content…

This enzyme catalyzes the hydrolysis of monoesters of phosphoric acid and transphosphorylation reaction under large phosphate concentration condition3. Alkaline phosphatase in E. coli periplasmic, which is passive diffuse of solutes occur mainly through porins in the outer membrane. The outer membrane serves as a diffusion barrier separating a population of periplasmic enzyme from substrate. Alkaline phosphatase assays were conducted with intact cells, and the substrate concentration at half-maximum velocity (Km) was determined as a function of enzyme concentration per cell. Diffusion of substrate to the enzyme cause changing in

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