The practical internship was carried out to study the effect of pH on the reaction of the acid phosphatase enzyme. Of the many functions of proteins, catalysis is by far the most vital. In the absence of catalysis, most reactions in biological systems proceed very slowly to occur at a rate adequate for the organism's metabolism. The catalysts that play this role are called enzymes. Enzymes are the most effective catalysts; they can increase the reaction rate up to 1,020 times compared to uncatalyzed reactions. (Campbell et al, 2012). Enzyme catalysis depends on factors such as enzyme and substrate concentration, temperature and pH. These factors determine the reaction rate, and an increase in temperature or pH above the optimum will cause the enzyme to denature and decrease the reaction rate. There are many phosphatase enzymes, but they are classified as those with optimal alkaline and acidic pH. Both catalyze the general reaction: ROPO3H2+ H2O –ROH + HPO42-+2H+. Each enzyme operates within a small pH range; there is a pH at which its activity is greatest, called optimal pH. This is because changes in pH can cause intra- and intermolecular bonds to break, distorting the shape of the enzyme and its effectiveness. Generally, enzymes have an optimal pH, this does not mean that the optimum is the same for each enzyme. For example, the optimal pH of the enzyme pepsin found in the acidic lumen of the stomach is lower than that of the enzyme carbonic anhydrase which acts in the cytosol at neural pH. The enzymes primarily exhibit specificity for phosphatase monoesters, but are relatively nonspecific for (RO- ). This can be used to construct an assay that uses a nonphysiological substrate, p-nitrophenyl phosphate, and one that has a middle of paper ......test) would allow a clear distinction in determining the variation in the data . However, the mean can sometimes show a simple interpretation of a distorted view of the distribution (outliers). The standard deviation gives the right picture, the smaller the standard deviation, the higher the central tendency and the data is concentrated around the mean. A higher value of the standard deviation indicates a better distribution of the data. Thus, a specific reading on the optimal pH can be identified. Word count = 1599ReferencesCampbell, MK, Shawn, SO (2012). Biochemistry, 7th edition. The behavior of proteins: enzymes. Pages 139-159. Van Etten, RL and Waymack, PP (1991). Substrate specificity and pH dependence of homogeneous wheat germ acid phosphatase. Archives of Biochemistry and Biophysics 288, 634.Walsh, C. (1979) Enzymatic Reaction Mechanisms, WH Freeman, San Francisco.