Considerations about the inhibition of monophenolase and diphenolase activities of tyrosinase. Characterization of the inhibitor concentration which generates 50 % of inhibition, type and inhibition constants. A review

• Published in: International journal of biological macromolecules 2024-05, Vol.267 (Pt 2), p.131513, Article 131513
• Main Authors: García Molina, Pablo, Saura-Sanmartin, Adrian, Berna, Jose, Teruel, Jose Antonio, Muñoz Muñoz, Jose Luis, Rodríguez López, Jose Neptuno, García Cánovas, Francisco, García Molina, Francisco
• Format: Article
• Language: English
• Subjects: Degree of inhibition; Diphenolase activity; Enzyme Inhibitors - chemistry; Enzyme Inhibitors - pharmacology; Humans; IC50; Inhibition; Inhibitory Concentration 50; Kinetics; Monophenol Monooxygenase - antagonists & inhibitors; Monophenol Monooxygenase - chemistry; Monophenol Monooxygenase - metabolism; Monophenolase activity; Oxidoreductases - antagonists & inhibitors; Oxidoreductases - metabolism; Tyrosinase
• ISSN: 0141-8130; 1879-0003; 1879-0003
• DOI: 10.1016/j.ijbiomac.2024.131513

Tyrosinase is a copper oxidase enzyme which catalyzes the first two steps in the melanogenesis pathway, L-tyrosine to L-dopa conversion and, then, to o-dopaquinone and dopachrome. Hypopigmentation and, above all, hyperpigmentation issues can be originated depending on their activity. This enzyme also promotes the browning of fruits and vegetables. Therefore, control of their activity by regulators is research topic of great relevance. In this work, we consider the use of inhibitors of monophenolase and diphenolase activities of the enzyme in order to accomplish such control. An experimental design and data analysis which allow the accurate calculation of the degree of inhibition of monophenolase activity (iM) and diphenolase activity (iD) are proposed. The IC50 values (amount of inhibitor that causes 50 % inhibition at a fixed substrate concentration) can be calculated for the two activities and from the values of IC50M (monophenolase) and IC50D(diphenolase). Additionally, the strength and type of inhibition can be deduced from these values. The data analysis from these IC50D values allows to obtain the values of KI1app or KI2app, or KI1app and KI3app from the values of IC50M. In all cases, the values of the different KIapp must satisfy their relationship with IC50M and IC50D. [Display omitted] •The IC50M can be obtained from the degree of inhibition of monophenolase activity.•The IC50D can be obtained from the degree of inhibition of diphenolase activity.•The values of IC50M and IC50D can help deduce the type of inhibition.•There is a relationship between the inhibition constants and IC50M and IC50D.