Enzyme, Protein, Carbohydrate, and Phenolic Contaminants in Commercial Tyrosinase Preparations: Potential Problems Affecting Tyrosinase Activity and Inhibition Studies

• Published in: Journal of agricultural and food chemistry 2008-06, Vol.56 (12), p.4760-4768
• Main Authors: Flurkey, Allison, Cooksey, Jena, Reddy, Akhila, Spoonmore, Kelli, Rescigno, Antonio, Inlow, Jennifer, Flurkey, William H
• Format: Article
• Language: English
• Subjects: accuracy; Agaricus - enzymology; Agaricus bisporus; amino acid sequences; Biological and medical sciences; carbohydrate content; carbohydrates; Carbohydrates - analysis; catechol oxidase; chemical composition; Drug Contamination; enzyme activity; enzyme inhibitors; Enzyme Inhibitors - pharmacology; enzymes; Enzymes - analysis; experimental design; Food Chemistry/Biochemistry; food contamination; Food industries; Fundamental and applied biological sciences. Psychology; glycosidases; inhibitors; isozymes; molecular sequence data; Monophenol Monooxygenase - chemistry; Monophenol Monooxygenase - metabolism; mushrooms; peptides; phenolic compounds; phenolics; Phenols - analysis; protein content; proteins; Proteins - analysis; Proteins - chemistry; tyrosinase
• ISSN: 0021-8561; 1520-5118
• DOI: 10.1021/jf800109a

Commercial mushroom tyrosinase contains other proteins, enzymes, carbohydrates, and phenolic material besides tyrosinase. Carbohydrate and phenolic material comprise a large percentage of the powder resuspensions derived from Agaricus bisporus. Enzyme assays identified the presence of tyrosinase, laccase, β-glucosidase, β-galactosidase, β-xylosidase, cellulase, chitinase, xylanase, and mannanase in the commercial tyrosinase. Protein sequencing indicated the presence of tyrosinase, a lectin, and a putative mannanase as well as 10 unidentified protein/peptides in the commercial tyrosinase preparations. Characteristics of tyrosinase isoforms were similar in two different commercial tyrosinase sources. Inhibition studies indicated that I 50 values for some tyrosinase inhibitors were different when the crude powder was compared to a partially purified tyrosinase. The presence of these contaminants has the potential to affect studies using commercial tyrosinase.