Abstract Objective:To study main biochemical characterization of a group of earthworm Desoxyribonucleases(EWDs). Methods:SDS-PAGE and MADLT-TOF ,enzyme activity detecting method were used to determine EWD1，EWD2, EWD3. Results:The molecular weights of EWD1, EWD2, EWD3 were 157.2kDa、69.1kDa and 63.5kDa respectively. Enzymological studies showed Kms of three EWDs were 1.58, 3.95 and 1.52 mg /ml. These 3 Dnases are sensitive to temperature, they do not display activity when the temperature rises to 55 degree. The optimal pH was between 4.0-5.6. Mn2＋、Ca2＋ are inhibiters for their activities, and Mg2+ had impact on EWD3 activities. Conclusion:Their MWs are apparently larger than DNaseⅠand DNaseⅡ. Temperature stabilities, pH stabilities, stimulant and antagonist studies were conducted on EWDs, the parameters of these effective factors were different from that of present Dnases. The above indicated that EWDs found in Lumbricus Bimastus had special enzymological characters and were new DNases, which were different from DnaseⅠand DNase II their catalytic mechanisms and classification wait to be studied and sorted.
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