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Enzymes are biocatalysts of protein in nature, which accelerate the rate of biochemical reactions but do not affect the nature of final product. Like catalyst the enzymes regulate the speed and specificity of reaction without being used up but unlike catalysts enzymes are produced by the living cells only. Like catalysts enzymes also influence the rate of biochemical reaction so that they can take place at a relatively low temperature. Thus the enzymes are known to lower the activation energy. In many cases enzymes initiate the biological reaction. The term enzymes are derived from Greek word enzymes which means ‘in yeast’ because the yeast cells were first to reveal the enzyme activity in living organisms. The term enzyme was coined by W. Kuhne in the year 1878. Properties Of Enzymes Can Be Classified Into:
Physical Properties of Enzymes
Chemical Properties Of Enzymes
General Properties Of Enzymes
Chemical Nature of Enzymes All enzymes are proteins, however all proteins are not enzymes. However, there are some conjugated enzymes with a non-protein moiety attached to the protein part of enzyme, which is called Apo enzyme. The non-protein part is known as co factor. If the co factor is of inorganic nature like potassium calcium, magnesium, manganese it is known as prosthetic group. Prosthetic group is generally tightly bound to the protein part of enzyme and it is difficult to separate it with simple method like diffusion. The enzyme with prosthetic group and Apo enzyme is called holoenzyme. If co factor attached to an enzyme protein is organic moiety like NADP, NAD, FAD, etc , it is called coenzyme. A co enzyme is generally loosely bound to Apo enzyme and can easily be separated than prosthetic group. Co enzymes are heat resistant also. Difference between Apo enzyme and co-factor:
The Most Important Properties Of An Enzyme Are:
Catalytic Property:Enzymes have extra-ordinary catalytic power. They are active in very small quantities. A small amount of enzyme is enough to convert a large quantity of substrate. The enzymes remain unchanged after the reaction. The turnover number of enzymes ranges from 0.5 to 600000. Turn over number is the number of substrate molecules converted by one molecule of enzymes per second when its active site is saturated with substrate. Specificity:Enzymes are very specific in their action. Particular enzymes act on particular substrates only. Enzymes are also specific to a particular type of reaction. In some rare cases, the specificity may not be too strong. Enzymes show different types of specificity as follows:
Reversibility:Most of the enzymes catalysed reactions are reversible. The reversibility of the reaction depends upon the requirements of the cell. In some cases, there are separate enzymes for forward and reverse reaction. Some enzyme-catalysed reactions are not reversible. Sensitivity To Heat, Temperature And pH:Enzymes are very sensitive to heat and temperature. They are thermolabile. The maximum activity of Associate in Nursing protein is at traditional temperature. The correct temperature for the utmost activity is termed optimum temperature. Enzymes will be inactive at very low temperatures; this is the reason for preserving food and vegetables in the refrigerator. The enzymatic activity increases with the increase in temperature up to a certain level. At higher temperature (60-70 degree Celsius), the enzyme is destroyed or denatured. Do you know an enzymes active at very high temperature? It is Taq-Polymerase used in PCR reactions. The optimum temperature for it is 75 to 80 degrees Celsius. The optimum pH of most endo-enzyme is pH 7.0 (neutral pH). However, digestive enzymes can function at different pH. For example, salivary amylase act best at pH 6.8, pepsin act best at pH2 etc. Any fluctuation in pH scale from the optimum causes ionization of R-groups of amino acids that decrease the protein activity. Sometime a change in pH causes the reverse reaction, e.g. at pH 7.0 phosphorylase break down starch into glucose 1- phosphate while at pH5 the reverse reaction occurs.
Enzymes are biocatalysts of protein in nature, which accelerate the rate of biochemical reactions but do not affect the nature of final product. Like catalyst the enzymes regulate the speed and specificity of reaction without being used up but unlike catalysts enzymes are produced by the living cells only. Like catalysts enzymes also influence the rate of biochemical reaction so that they can take place at a relatively low temperature. Thus the enzymes are known to lower the activation energy. In many cases enzymes initiate the biological reaction. The term enzymes are derived from Greek word enzymes which means ‘in yeast’ because the yeast cells were first to reveal the enzyme activity in living organisms. The term enzyme was coined by W. Kuhne in the year 1878. Properties Of Enzymes Can Be Classified Into:
Physical Properties of Enzymes
Chemical Properties Of Enzymes
General Properties Of Enzymes
Chemical Nature of Enzymes All enzymes are proteins, however all proteins are not enzymes. However, there are some conjugated enzymes with a non-protein moiety attached to the protein part of enzyme, which is called Apo enzyme. The non-protein part is known as co factor. If the co factor is of inorganic nature like potassium calcium, magnesium, manganese it is known as prosthetic group. Prosthetic group is generally tightly bound to the protein part of enzyme and it is difficult to separate it with simple method like diffusion. The enzyme with prosthetic group and Apo enzyme is called holoenzyme. If co factor attached to an enzyme protein is organic moiety like NADP, NAD, FAD, etc , it is called coenzyme. A co enzyme is generally loosely bound to Apo enzyme and can easily be separated than prosthetic group. Co enzymes are heat resistant also. Difference between Apo enzyme and co-factor:
The Most Important Properties Of An Enzyme Are:
Catalytic Property:Enzymes have extra-ordinary catalytic power. They are active in very small quantities. A small amount of enzyme is enough to convert a large quantity of substrate. The enzymes remain unchanged after the reaction. The turnover number of enzymes ranges from 0.5 to 600000. Turn over number is the number of substrate molecules converted by one molecule of enzymes per second when its active site is saturated with substrate. Specificity:Enzymes are very specific in their action. Particular enzymes act on particular substrates only. Enzymes are also specific to a particular type of reaction. In some rare cases, the specificity may not be too strong. Enzymes show different types of specificity as follows:
Reversibility:Most of the enzymes catalysed reactions are reversible. The reversibility of the reaction depends upon the requirements of the cell. In some cases, there are separate enzymes for forward and reverse reaction. Some enzyme-catalysed reactions are not reversible. Sensitivity To Heat, Temperature And pH:Enzymes are very sensitive to heat and temperature. They are thermolabile. The maximum activity of Associate in Nursing protein is at traditional temperature. The correct temperature for the utmost activity is termed optimum temperature. Enzymes will be inactive at very low temperatures; this is the reason for preserving food and vegetables in the refrigerator. The enzymatic activity increases with the increase in temperature up to a certain level. At higher temperature (60-70 degree Celsius), the enzyme is destroyed or denatured. Do you know an enzymes active at very high temperature? It is Taq-Polymerase used in PCR reactions. The optimum temperature for it is 75 to 80 degrees Celsius. The optimum pH of most endo-enzyme is pH 7.0 (neutral pH). However, digestive enzymes can function at different pH. For example, salivary amylase act best at pH 6.8, pepsin act best at pH2 etc. Any fluctuation in pH scale from the optimum causes ionization of R-groups of amino acids that decrease the protein activity. Sometime a change in pH causes the reverse reaction, e.g. at pH 7.0 phosphorylase break down starch into glucose 1- phosphate while at pH5 the reverse reaction occurs. |