Enzyme are highly effective as catalysts

Because of the precise chemical fit between the active site of an enzyme and its substrates, enzymes are highly effective as catalysts.

- DR TAPAN KUMAR MAITRA

This effectiveness can be seen in the much greater extent to which reaction rates are catalyzed by enzymes compared with inorganic catalysts. As we noted previously, enzyme-catalyzed reactions proceed 107 to 1014 times faster than uncatalyzed reactions, versus 103 to 104 times faster for inorganic catalysts. As you might guess, most of the interest in enzymes focuses on the active site, where binding, activation, and chemical transformation of the substrate occur.

Substrate Binding: Initial contact between the active site of an enzyme and a potential substrate molecule depends on random collision. Once in the groove, or pocket, of the active site, however, the substrate molecules are bound temporarily to the enzyme surface in just the right orientation to one another and to specific catalytic groups on the enzyme to facilitate reaction. Substrate binding usually involves hydrogen bonds or ionic bonds (or both) to charged amino acids. These are generally weak bonds, but several bonds may hold a single molecule in place. The strength of the bonds between an enzyme and a substrate molecule is often in the range of 3-12 kcal/mol, less than one-tenth the strength of a single covalent bond. Substrate binding is therefore readily reversible.

ENERGIES OF BIOLOGICALLY IMPORTANT BONDS AND TRANSITIONS