Enzymes
ENZYMES
Biological catalysts which speed up the rate of reaction without becoming part of the reaction but themselves cannot initiate any chemical reaction.Enzymes are the most important groups of proteins exhibiting biological activity.These proteins are catalysts responsible for driving chemical reactions within the cell.Unlike inorganic catalysts, an enzyme displays an unusual degree of specificity, both with regard to the substrate on which it acts and the type of reaction it catalyzes.
Being a biological catalyst, enzymes share some properties with chemical catalysts
a. Enzymes are neither consumed nor produced during the course of a reaction.
b. Enzymes do not cause reactions to take place, but they greatly enhance the rate of reactions that would proceed much slower in their absence. They alter the rate but not equilibrium constants of reactions they catalyse.
Difference between enzymes and chemical catalysts;Enzymes are proteins,Enzymes are highly specific and produce only the expected products from the given reactants, or substrates (i.e, there are no side reactions)Enzymes may show a high specificity towards one substrate or exhibit a broad specificity, using more than one substrate. Enzymes usually function within a moderate pH and temperature range.
Enzymes specificity
Enzyme specificity determines the fate of a compound. For instance, the reaction of glucose-6-phosphate depends on the enzyme that acts on it, there being at least four well characterized enzymes that convert this compound to four different products (P = phosphate)
Measures of enzyme activity
Specific activity •Is usually expressed as µmol of substrate transformed to product per minute per milligram of enzyme under optimal conditions of measurement.
Turnover number or kcal,Is the number of substrate molecules metabolized per enzyme molecule per unit time with units of Min-1 or S-1
Biological catalysts which speed up the rate of reaction without becoming part of the reaction but themselves cannot initiate any chemical reaction.Enzymes are the most important groups of proteins exhibiting biological activity.These proteins are catalysts responsible for driving chemical reactions within the cell.Unlike inorganic catalysts, an enzyme displays an unusual degree of specificity, both with regard to the substrate on which it acts and the type of reaction it catalyzes.
Being a biological catalyst, enzymes share some properties with chemical catalysts
a. Enzymes are neither consumed nor produced during the course of a reaction.
b. Enzymes do not cause reactions to take place, but they greatly enhance the rate of reactions that would proceed much slower in their absence. They alter the rate but not equilibrium constants of reactions they catalyse.
Difference between enzymes and chemical catalysts;Enzymes are proteins,Enzymes are highly specific and produce only the expected products from the given reactants, or substrates (i.e, there are no side reactions)Enzymes may show a high specificity towards one substrate or exhibit a broad specificity, using more than one substrate. Enzymes usually function within a moderate pH and temperature range.
Enzymes specificity
Enzyme specificity determines the fate of a compound. For instance, the reaction of glucose-6-phosphate depends on the enzyme that acts on it, there being at least four well characterized enzymes that convert this compound to four different products (P = phosphate)
Measures of enzyme activity
Specific activity •Is usually expressed as µmol of substrate transformed to product per minute per milligram of enzyme under optimal conditions of measurement.
Turnover number or kcal,Is the number of substrate molecules metabolized per enzyme molecule per unit time with units of Min-1 or S-1
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