Enzyme Numbers and Classification

EC Numbers Enzymes are classified into six different groups according to the reaction being catalyzed The Nomenclature was determined by the Enzyme commission in 1961 ( with the latest-update having occured in 1992), hence all enzymes are assigned an "EC" number . EC numbers are four digits / for example a.b.c.d where a class . b Sublass describe the rear C Sub - Subdass d Sub -sub-subclass - used to distinguish b/w Ex For Alcohol: NAD+ oxidoreductare. diff enzymes of the same function based on the actual ECno. = 1.1.1.1 Substrate in the rean Six classes EC 1 - Oxidoreductase. - Catalyze the transfer of H/Oxygen atoms or e from one Substrate to another , also called oxidases, dehydrogenaso Or reductasa Since there are 'redox' reare an I donor /acceptor is also required to complete the rean. eg- pyruvate NADH + H lactate + NAD+ Ec. 2. Transferares LDH - Catalyze group transfer reans excluding Oxidoreductave (which transfer hydrogen / oxygen and are ECA)

A- X + B B-X+A eg EC Apartate + Carbamay phosphate Asportate 3. Hydrolasei (arbarry laspartate++ phosphate - latalyze hydrolytic. reaction Includes lipases, / esterases nitrilases, peptidascs 1 proteases. A -X +H2O 6 X-OH + HA eg- EC Glu- 4. -6-phosphate Lyance + H2O greta glucose -6 phosphatas glucose + Pi - latalyze non hydrolytic (covered in EC3) removal of functional gp from substrates, often creating a double bond in the product; or the reverse reaction, ie, addn of function gps across a double bond. . A-B A=B+X-Y. + Xy eg:- & L-malate fumarate fumarate + H2O Includes decarboxylaser and aldolases hydratase. in the removal direction, and Synthases in the addn direction. EC 5. Isomerases - Catalyzes isomerization reans including racemization and cis trans isomerizations. eg: L- alanine Alanine D-alanine - EC 6. Ligases racemase - Catalyzes the Synthesis of various (mostly (-x) bonds , coupled with the breakdown of energy - containing substrates, usually ATP. la: Glutamate + ATP NHat Glutamine synthetase Glutamine + ADP+ Pi

Carbon atome encountered in biochemistry can exist In five Oxdn states, depending on the elements with which Carbon shares electrons. - (H2- CH3 Alkane - -CH2- - CH2OH Alchhol - -CH2- Aldehyde (ketone) H(R) O - CH2- d OH Carboxylic acid O- C=O Carbon dioxide. . Oxdn Redn reactions free energy changes are associated In many biological Oxdne a compound loses two electrone and two hydrogen ions (that is, two hydrogen atoms); these reactions are commonly called dehydrogenation and the enzymes that Catalya them are called dehydroganasci. In some , but not all / biological oxdns, a carbon atom becomes covalently bonded to an oxygen atom. The entymes that Catalyze these oxdne are generally called oxidare Or if the oxygen atom is derived directly from molecular Oxygi (02), oxygenase

- Every oxdn must be accompanied by a redn, , in which an C acceptor acquires the electrone removed by oxdn. OH 2H++20 CH3-CH- [" I 0 CH3 C O- 21+++20 O- lactate lactate pyouvate Dehydrogenasc fig- oxdn redn rean. lactate oxdn pyruvate. Here, in this dehydrogenation 2 es and 2 Hydrogen ions (the equivalent of two hydrogen atome) are removed from C-2 of lactate ,an alcohol, to form provate, a ketone. In cells the rean is catalyzed by lactate dehydrogenase and the ts are transferred to a cofactor called nicotinamide adenine dinucleotide. This rean is fully reversible pyruvate can be reduced by es from the cofactor.