Enzymes activity plays an important role on living organisms. Its activity can be affected by different factors, including environmental and molecular elements. Enzyme inhibition by some molecules can be competitive or noncompetitive according to the binding mechanism. The aim of this study was to determine the type of inhibition occurred by the phenylthiourea (PTU) on the catechol oxidase enzyme. Different substrate concentrations, 0.5, 1, and 1.5 mL, and presence (1mL) and absent of PTU was analyzed. Products were measured at 380 nm. Results showed product only when PTU was not present, except for in one tube. A PTU noncompetitive inhibition is proposed based on the inability to obtained product even when the substrate concentration is increased. …show more content…
al., 1998). It catalyzes the conversion of a large number of catechols producing a dark pigment called melanin, which is the product of the chemical reaction. Studies on enzyme activity are important in order to establish some controls. In particular, with regards to the cathecol oxidase, its inhibition can help to reduce the pigment production and the darkness of some vegetables and fruits. This is obviously very significant for the marketing of food products, as people usually do not like it to be dark, even if there is nothing wrong with it; the color itself influences their …show more content…
One bases this difference on the ability of the inhibitor and the substrate to bind to the enzyme. Competitive inhibition is when a molecule that is structurally similar to the substrate for a particular reaction competes for a position at the active site of the enzyme. This involves the enzyme so it is not available for the substrate; therefore, it becomes unable to produce its catalytic reaction. On the other hand, noncompetitive inhibition is done by an inhibitor that binds to a part of the enzyme that is not the active site. In doing so, the inhibitor changes the nature of the enzyme as well as its catalytic properties. If the substrate concentration is increased, the inhibition can be overcome in competitive inhibition. However, this is not possible in noncompetitive