Partial Purification and Estimated some Characterization of protease from prickly lettuce (Lactuca serriola L.) leaves and used it in some applications


Abstract: Acetone powder was used to extracted protease from (Lactuca serriola L.) Prickly lettuce leaves. Enzyme content of crude extract was concentrated by gradual addition of ammonium sulfate at 40-80% saturation, then partial purification of gel filtration chromatography by sephacryl S-200. The enzyme specific activity, purification fold and yield were 51.37 unit/mg, 6.30 and 77.55 respectively. The molecular weight was 31000 Dalton as determined by gel filtration. The results were showed that optimum pH of the purified enzyme by used casein as a substrate was 8.5 while the enzyme was stable at a wide range of pH that between 4-10. The optimum temperature for enzyme activity was 60ºC and the enzyme was stable at 55ºC for 30 min. The results refer to increase in enzyme activity when treated with Mg, Ca and Zn 114.09, 128.63 and 118.43 respectively while treatment with Co and Hg lead to lose near 50 and 95% from enzyme relative activity, but these activity was not high affected when using all of phenyl methyl sulfonyl fluoride (PMSF), Pepstatin and Ethylene Diamine Tetra Acetic acid (EDTA) that 94.37, 96.27 and 91.93 respectively, while the enzyme relative activity was 105.37 when used β-mercaptoethanol, but used Iodoacetic acid lead to get 22.76% form original enzyme activity. The chemical enzyme modification by using Polyethylene glycol (PEG) that activated with Cyanuric chloride (CC) lead to increased of enzyme relative activity alkaline pH value and high temperature degree. The results of application study refer to the ability to use protease in dehairing from cow skin after soaked for 24 hours, and when enzyme was used with commercials detergents. It was noticed that the non modified enzyme had (89, 84, 82, 76 , 69%) from its original activity, while the modified enzyme at 72% had (94, 86, 85, 82, 76 , 74%) from its original activity after incubation at 50ºC for 30 minutes with commercial detergents like Persil, Bonux, Ariel, Tide and Alwazir respectively.