| Acid phosphatase, referred to ACP, is a kind of inducible enzyme, which can hydrolyze the single phosphate ester of substrate in the acidic condition and is one of the key enzymes in the process of phosphorus metabolic of biological system. ACP is not only closely allied to physiological function such as growth regulating,metabolic regulation,signal transduction and so on, but also enhances resistance adversity such as Phosphorus deficiency,drought,cold and so on for plant. So it is caused Extensive attention by scholars in recent years.Mung bean is the Annual herb and is belonging to Legume family-papilionaceae-cowpea genera. It's originated from India and the Nile valley. It is a kind of natural green plants, which has integrated with nutrition and health care, food and fodder, antibiosis and diminish inflammation. Mung bean has a high nutritional value, for example, its protein content is 3 times than japonica's, as well as it contains a variety of vitamins,calcium,phosphorus,iron and inorganic salts. Mung bean is sweet, cold, and it can clear away heat and toxic material and can improve eyesight.Meanwhile the mung bean garment extract also has the obvious antibacterial bacteriostasis, therefore great attention has been paid in the medical circle. In recent years, more and more researches of mung bean has been done, among which JI-2 of mung bean matches the main inducing produces ACP conditions owing to its comparative tolerant to drought,resistant pain, disease resistance,strongly good performance of environmental stress adaptability. Meanwhile, in legumes, JI-2 of mung bean has less protein relatively, which is good for separation and purification.At present the separation and purification of mung bean acidic phosphatase has not been reported, so this paper, in which the study object is form JI-2 of mung bean sprouts and more researches has been done on separation and purification, physical and chemical properties, enzyme kinetics characteristics, inhibitor and functional groups of chemical modification and so on, can be supported to the further study of ACP and be useful for farming improvement and crop's genetic improvement.The results of our study are as followed:1.Purification of ACP from mung bean sprouts The ACP was extracted by ammonium sulfate Precipitation, and ion-exchange chromatography on DEAE-Sepharose, and gel filtration on Superdex-200.SDS-PAGE was used to ideniify the Purity of the ACP.The enzyme was purified to electrophoretic homogeneity.it was purified 156.3-fold and the activity recovery 4.0 Percent was obtained.Its specific aectivity was 347.0U/mg.2.Properties of ACP from mung bean sproutsThe relative molecular weight of this ACP was 34.6kD, and the weight of subunit was 33.1 kD.So the ACP consists of one identical subunits.Studies on the properties of the ACP showed that the optimum temperature was 40℃and the optimum pH was 5.2.The apparent Km of this enzyme was 4.28×10-3 mol/L.3.Inhibitors of ACP from mung bean sproutsAmong several mental ions, Mg2+,Co2+can activate the enzyme activity, Hg2+, Cu2+, Pb2+ and Zn2+ are strongly inhibited the activity,and the order is:Hg2+>Cu2+>Pb2+>Zn2+. The enzyme was not sensitive to K+,Ca2+.Organic solvent:methanol, ethanol, ethylene alcohol and isopropyl alcohol inhabited its activity. Vitamin C inhabited ACP activity obviously. Carbamide and EDTA did not have obvious effect on ACP.H2O2 had double effect on ACP as in low concentration it activated ACP and showed no effect over 50 mmol/L.4.Chemical modification of ACP from mung bean sproutsChloramine-T, PCMB, NBS and PMSF inhabited its activity obviously, and the reduction of its activity related to the concentration of modifier.So Met, Trp and Ser may be the essential group in Mung Bean ACP's active center.On the contrary, SUAN, DTT, BrAc and Hacac did not inhabit its activity which means that His, Arg and Lys did not Maintain the enzyme activity.
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