Page 31 - Enzymes in Tropical Soils

Enzymes in Tropical Soils 19

0
E = H* - H R ....... Eq. 2.4

where H* is Enthalpy of reactants at activated state or Activation Energy in
Arrhenius Equation. To produce the reaction products, the reactants must suffice
the amount of energy as high as E, otherwise the reactants will stay as they are and
the products will never exist.

H
Activated State

*
H
0
H* - H R

0
H R
0
Reactants H
0
H P
Products

Fig 2.2. Variation of enthalpy in a reaction (After Castellan, 1983).

The presence of enzyme is reported to lower the Activation Energy to a
lower value and enables the reactions to pass the energy barrier so that it may
change the reactants into the reaction products. The presence of enzymes may
then increase the rates of the biochemical reactions.

2.4 Zero Order Enzyme Reaction

As stated previously, the determination of enzyme activities is performed at
high concentration of substrate in order to obtain the highest rates of enzymatic
reaction. The reason for this is that the concentration of enzyme and substrate are

Abdul Kadir Salam - 2014