Phenolase in Norway lobster (Nephrops norvegicus): activation and purification

Increase in phenolase activity from Norway lobster was observed to take place immediately after making a crude enzyme preparation; the total enzyme activity increased by a factor of 3–4 over a period of 8–12 h. The process was associated with the appearance of a more active form of the phenolase. The initial natural form (Form I) and the more active form (Form II) of the enzyme were separated and partially purified by a combination of acetone precipitation and DEAE cellulose column chromatography. The natural form (Form I) was found to have an optimum temperature of 40°C, an isoelectric point of 4·7, a molecular weight of 667 000 and a Km towards catechol of 21·8 mm, whereas the more active form (Form II) was found to have an optimum temperature of 45°C, an isoelectric point of 6·1, a molecular weight of 141 000, and a Km towards catechol of 2·84 mm.