what are the enzymes how are their classified
Answers
Explanation:
Enzymes are classified into six categories according to the type of reaction catalyzed: Oxidoreductases, transferases, hydrolases, lyases, ligases, and isomerases. Structurally, the vast majority of enzymes are proteins. Also RNA molecules have catalytic activity (ribozymes).
Explanation:
Enzymes are catalysts that, within the mild conditions of temperature, pH, and pressure of the cells, carry out chemical reactions at amazing high rate. They are characterized by a remarkable efficiency and specificity.
Substrates are the substances on which enzymes act.
Enzymes are named by adding the suffix -ase to the name of the substrate that they modify (i.e., urease and tyrosinase), or the type of reaction they catalyze (dehydrogenase, decarboxylase). Some have arbitrary names (pepsin and trypsin). The International Union of Biochemistry and Molecular Biology assigns each enzyme a name and a number to identify them.
Enzymes are classified into six categories according to the type of reaction catalyzed:
Oxidoreductases, transferases, hydrolases, lyases, ligases, and isomerases.
Structurally, the vast majority of enzymes are proteins. Also RNA molecules have catalytic activity (ribozymes).
Coenzymes are small nonprotein molecules that are associated to some enzymes. Many coenzymes are related to vitamins. Coenzymes and the protein portion with catalytic activity or apoenzyme form the holoenzyme. The apoenzyme is responsible for the enzyme’s substrate specificity. Coenzymes undergo changes to compensate for the transformations occurring in the substrate.
Metalloenzymes are enzymes that contain metal ions.
The mechanism of action of enzymes depends on the ability of enzymes to accelerate the reaction rate by decreasing the activation energy. During the course of the reaction, the enzyme (E) binds to the substrate/s (S) and forms a transient enzyme–substrate complex (ES). At the end of the reaction, the product/s are formed, the enzyme remains unchanged, can bind another substrate and can be reused many times.
Active site or catalytic site is the specific place in the enzyme where the substrate binds. The structural complementarity between E and S allows an exact reciprocal fit. The enzyme adapts to the substrate via a conformational change known as induced fit. The presence in the active site of amino acids that bind functional groups in the substrate ensures adequate location of the substrate and formation of the transition intermediary, which will be subjected to catalysis.
Zymogens or proenzymes are inactive precursors of enzymes. They acquire activity after hydrolysis of a portion of their molecule.
Cellular location of enzymes varies, the majority being in different compartments of the cell, while others are extracellular.
Multienzyme systems are those composed of a series of enzymes or enzyme complexes. There are also multifunctional enzymes with several different catalytic sites in the same molecule.
Enzyme activity is determined by measuring the amount of product formed, or substrate consumed in a reaction in a given time. Initial velocity corresponds to the activity measured when the amount of consumed substrate is less than 20% of the total substrate originally present. One IU of enzyme catalyzes the conversion of 1 μmol of substrate per second under defined conditions of pH and temperature. Specific activity is the units of enzyme per milligram of protein present in the sample. Molar activity or turnover number are the substrate molecules converted into product per unit time per enzyme molecule, under conditions of substrate saturation.