Salivary amylase is an enzyme found in the mouth. it speeds up the reaction of breaking down starch into sugars. why will salivary amylase only speed up the break down of carbohydrates and not proteins? ? a* the enzyme is the wrong substrate for proteins. b* proteins will not fit into the active site of the amylase enzyme. c* proteins will never get broken down into smaller molecules like carbohydrates. salivary amylase is an enzyme found in the mouth. it speeds up the reaction of breaking down starch into sugars. why will salivary amylase only speed up the break down of carbohydrates and not proteins?