Choose the correct sequence of of steps in catalytic cycle of an enzyme action.

I. Breakage of chemical bonds or making of chemical bonds in the substrate/s

II. Binding of substrate to the active site of enzyme

III. Release of product from the active site of enzyme.

IV. Fitting of substrate more tightly by the enzyme at the active site.

Various steps in the catalytic cycle of an enzyme action.

1. Binding of substrate at the active site of enzyme. 
2. Binding of substrate at the active site induces the enzyme to alter its shape, fitting more tightly around the substrate.
3. Due to close proximity of substrate to active site of enzyme, the bonds are broken or made in the substrate and there is formation of enzyme product complex.
4. The product is released from the enzyme active site and the free enzyme is ready to bind to another molecule of substrate and run through another catalytic cycle.