Which of the statements about enzymes are true? generally, an enzyme is specific for a particular substrate. for example, thrombin catalyzes the hydrolysis of the peptide bond between arg and gly. an enzyme yields a specific product, whereas a nonbiological catalyst may produce more than one product with the occurance of side reactions. catalysis occurs at the active site, which usually consists of a crevice on the surface of the enzyme. nonbiological catalysts and enzymes tend to have a similar degree of reaction specificity. a substrate must bind to the active site before catalysis can occur.