Enzymes

Classification of Enzymes 

1) Oxidoreductase

2) Transferase

3) Hydrolase 

4) Lyase

5) Isomerase

6) Ligase

Ex: Hexokinase 2.7.1.1

A Stereotypical diagram of the Holoenzymes

Inhibition of Enzymes 
There are three different Inhibitions, Competitive inhibition, Noncompetitive inhibition, and uncompetitive inhibition.


Competitive Inhibition: 
The Inhibitor binds to the catalytic center or active site of the enzyme and prevents the substrate from binding on the enzymes. Eventually, the Michealis constant (Km) will be higher than the stage without any inhibitors. 

Diagram of Competitive Inhibitor

Figure 1 Competitive Inhibition

According to Michealis, it is hard to determine the Vmax by looking at the hyperbolic graph. Therefore, he took the reciprocal of the concentration of substrate and the velocity, which allowed him to graph the inverse of hyperbola or Linear. As shown in the Figure 1, the Vmax of the process can be determined by the y-intercept of the graph. 

NOTE: Competitive Inhibition: Vmax the same, Km Increase.



Source: Dr. Larry Jon Friesen' s Lectures 

Useful Link: http://www.rcsb.org/pdb/home/home.do