PURIFICATION AND PROPERTIES OF A FUNGAL L-ASPARAGINASE FROM TRICHODERMA VIRIDE PERS: SF GREY

摘要

A potent L-asparaginase-producing Trichoderma viride Pers: SF Grey was screened from the marine soil with the objective of studying the enzyme properties. The maximum enzyme production occurred on the third day at pH 6.5 and 37 °C when 0.5% L-asparagine supplemented with 0.5% peptone and 0.6% maltose. The enzyme was purified to homogeneity with a specific activity of 78.2 U.mg-1 and a molecular weight of 99 ± 1 kDa. It exhibited maximum activity at pH 7.0 and 37 °C. It was inhibited by Fe2+, Fe3+, Co2+ and Mn2+ but induced by Mg2+ and Na+. N-ethylemaleimide and phenylmethylsulphonylfluoride did not alter the enzyme activity, but strongly inhibited by ethylenediaminetetraacetate. L-asparaginase showed high affinity for L-asparagine with a Km of 2.56 μM. Thin layer chromatography confirmed the hydrolysis of L-asparagine. As the purified and characterized L-asparaginase of Trichoderma viride showed a good scavenging activity and reduced acrylamide level in potato products, it can further serve as an antileukemic protein and an acrylamide mitigation agent in heat-treated food stuffs rich in carbohydrates, respectively.