Production of plant proteinase from jack fruit (Artocarpus integrifolis) as a source of dairy enzyme I. Isolation, partial purification and some properties
2003
Al-Tanboly, A. (National Research Centre, Cairo (Egypt). Dairy Science Dept.)
The aim of the present work was to search for a novel plant proteinase enzyme from Jack fruit (Artocarpus integrifolis) as a source of dairy enzymes that would be natural products which can be easily extracted at relatively low cost and no legal barriers. This enzyme was subjected to a purification scheme composed of ammonium sulfate fractionation followed by gel filtration on G-100 Sephadex column. The enzyme was purified 2.70-fold with a total yield of 23.77% of the original activity. There were relationship between temperature and incubation time, the enzyme activity increase was observed up to 55 degree centigrade for 60 min reaction time and still constant thereafter. Proteinase was active over a broad temperature range retained about 37.4 and 24.9% of temperature activity at 35 and 80 degree centigrade for 5 and 60 min. An energy of activation of 9.98 KJ mole-1 for the enzyme activity was derived from the Arrhenius plot of initial velocity (V0) across a temperature ranging from 40 to 55 degree centigrade. The optimum pH was pH 7.5. The rate of thermal inactivation proceeded more rapidly at pH 7.0 and 8.0, when heating at 50 degree centigrade for 60 min the enzyme activity lost about 95 and 92% its activity, respectively. Michaelis-constant of (Km) values of 2.0 mg ml-1 and a maximum initial velocity (Vmax) of 0.75mu moles mg-1 when casein used as a substrate. A Molecular weight (MW) determination of 22 kDa was estimated by gel filtration methods using a Sephadex G-100. Cu2+, K2+ , Fe2+ and Zn2+ strongly inhibited the enzyme. However, Ca++ slightly stimulated. EDTA, sodium azide, Sodium citrate and urea among the chemical reagents inhibited the proteinase activity.
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