Molecular Vital Statistics: The Significance of Shape: A Review Article

Abstract

The living cell depends on its enzymes1 to carry out the chemical reactions necessary for its survival. Enzymes are catalysts; they increase the speed of chemical reactions without altering the nature or result of the reaction. As an example, consider lactase, the trivial name for an enzyme which is found in the lining of the intestine. (Its official name and number are /J-D-galactoside galactohydrolase, E.C. 3.2.1.23.2) It splits milk sugar (lactose) into two smaller sugars (glucose and galactose). This change occurs spontaneously, but only at an extremely slow rate. The enzyme is essential to allow this chemical reaction to occur sufficiently quickly for the sugar to be absorbed from the intestine.