Abstract: Laccase from Prickly lettuce leaves was purified through three sequential steps using (NH4)2SO4, ion-exchange and gel filtration chromatography. At the end of the process, enzyme was 17.04 fold purification and yield of 76.66% with a specific activity 141.996 U/mg. The molecular weight was 69.37 kDa as estimated by gel filtration chromatography (Sephacryl S-200). The visible absorption spectrum showed one peak at 618 nm that is typical for type I Cu (II). The optimum pH activity was 6 and enzyme was stable between 4-7, while temperature activity was 40 and enzyme was stable at 60°C for 15 min. Carbohydrate content of purified laccase was 12% as determined by phenol sulfuric acid, and enzyme was 100% inhibited by 10mM of Sodium azide, l-cysteine, dithiothreitol and EDTA and 98, 96, 94, 91, 93 and 82% by SDS, Hg+2, Al+2, Ba+2, Ni+2 and Mn+2 respectively at same concentration, while inhibition at 1Mm was 45, 39, 62, 59, 51, 53, 48, 55 and 41% respectively, and the Km and Vmax values was 53.68 μM and 641.2 μM\min respectively. The treatment of apple juice with 1, 5, 10, 20 u\mg of laccase led to removed 11.35, 44.72, 88.03 and 89.21 % of phenol compounds respectively, while the treated with 10 u\mg of laccase for 10, 20, 30, 40, 50, 60 min led to removed 28.42, 60.93, 88.03, 89.37, 90.01 and 90.04% of phenol compounds respectively.
Laccase, Prickly lettuce leaves, Lactuca serriola L., Purification, Phenolic compound, Apple juice.
Use of Purified Laccase from Prickly Lettuce (Lactuca serriola L.) In Removal of Phenolic Compound from Some Foods
Mohammed Abdulrazzaq Al-Soufi
International Journal of Novel Research in Life Sciences