Purification and properties of polyphenol oxidase from oil bean (Pentaclethra macrophylla Benth) seeds

✍ Scribed by Ferdinand C Chilaka; Emmanuel O Anosike; Patrick C Egbuna

• Publisher: John Wiley and Sons
• Year: 1993
• Tongue: English
• Weight: 250 KB
• Volume: 61
• Category: Article
• ISSN: 0022-5142
• DOI: 10.1002/jsfa.2740610120

✦ Synopsis

Abstract

Polyphenol oxidase extracted from oil bean (Pentaclethra macrophylla) seeds was purified 165‐fold over the crude enzyme extract. The apparent molecular weight of the enzyme by gel filtration was 110.8 k ± 9.0 k while SDS‐PAGE indicated a single species of molecular weight 28.0 k. A copper content of 1.9 mg g^−1^ corresponds to one copper atom for each of the four subunits. The purified enzyme oxidised pyrogallol, catechol, 4‐methylcatechol and L‐dihydroxyphenylalanine but had low activity towards tyrosine. p‐Cresol, caffeic acid and cholorogenic acid were not oxidised. Thio‐compounds were strong inhibitors of the enzyme. The phenolic compounds tyrosine, resorcinol and orcinol inhibited catechol oxidation but became oxidised in the process.