If the reactant and the catalyst are in the same phase then it is called as homogeneous catalysis. Acid-base catalysis and enzyme catalysis are the important types of homogeneous catalysis
Acid-base catalysis
This includes homogeneous reactions which are catalysed by acid, base or both.
The reactions which are catalysed by only H+ ions are called Specifically proton-catalysed reactions.
Examples are (i) solvolyis of esters (ii) inversion of cane sugar (iii) keto-enol transformation.The reactions which are catalysed by any Bronsted acid are called General acid –catalysed reactions.The reactions which are catalysed by only OH- ions are called Specifically proton-catalysed reactions.The reactions which are catalysed by any Bronsted bases are called General acid –catalysed reactions
Enzyme catalysis
Homogenous reactions which are catalysed by enzymes are included in this catalysis. Enzymes are proteins with high molecular masses. Generally enzymes are obtained from living organisms. Enzymes are specific in its activity ie. Each enzme catalyze a specific reaction
Michaelis Menten kinetics
L.Michaelis and Mary Menten in 1913 have proposed a mechanism for the kinetics of enzyme catalysed reaction. The mechanism of the enzyme kinetics involves two major steps (i) Formation of the Enzyme-substrate complex and (ii) Decomposition of the enzyme substrate complex. 
Here E→ Free enzyme
S→ Substrate
ES→ Enzyme Substrate complex P→ Product . The Michaelis Menten Equation is given by r = {k2[E]0 [S] } / { Km + [S] } Where Km is the Michaelis Menten constant.
Here E→ Free enzymeS→ Substrate
ES→ Enzyme Substrate complex P→ Product . The Michaelis Menten Equation is given by r = {k2[E]0 [S] } / { Km + [S] } Where Km is the Michaelis Menten constant.
Effect of temperature on Enzyme catalysis
Enzyme catalyst also decrease the activation of a reaction at a given temperature. The enzyme catalyst reduce the activation energy of a reaction to a considerably greater extent.Upto about 45°C the rate of the enzyme catalysed reaction increases with temperature. After 45°C thermal denaturation of the enzyme takes place. At about 55°C denaturation of enzymes occurs rapidly