Enzymes Thermodynamics

Thermodynamile First and second law can be combined for making the useful equation (energy changes) AG . = AH-TAS DG = free energy DH = chang in enthalpy. (heat content of the system). T Temperature n K (0°C (+273) D S = change in entropy. Free energy change Amount of energy available to do some useful work DG: = Standard free energy Total DS = amount of energy which cannot be used for performang work. a Air is negative ,The rean is Spontaneous and going to complete. DG is tve, spontaneous. A+B C+D The r can is in. equilibroun. Law of mass action , vate of rear & conc of pdts.

Keq = Con of pdts Cone of reactants. Keq= = [c] [o] (A] (B) if the rean is spontaneous ,Keq>, 1. Case/I A+B C+D Here forward rean is more. 2 6 to Keq = (c](o) (A] (B] Keg -- 3 - Keq = c/2 = . C.F.G Keq > I So DG is Negatic - the rean is spontaneous favourable rean. going to complete This type of rean is called exergonic reaction Care II A+B C+D Keq - (c](b) LI (n) (B) DG is +ve, / the rean is less favourable H requires external assistance for the completion. Endergonic reaction.

Endorgence . Ax A+B C+D ATP ADP+Pi External assistance. is AIP. The Pi will be used to make-the rean an exergonic rean. 19/04/29 ATP- - coupling agent NH2 N when ATP is added, N ATD ADP+Pi A+B C+D N 0 O i o CH2 I 0- 0- 0- ou OH ATP+H2O ADD+ pi DG: -7.3 Kcal/mol This will drive endergonuc reaction more to reaction.