CHARACTERIZATION OF ADENOSINE NUCLEOSIDASE FROM SOYBEAN SEEDS (Glycine max L.)

Abstract

The nucleoside salvage pathway plays a key role in the growth and development of plants. The activities of several enzymes of the nucleoside salvage pathway were determined in germinated soybean seeds. One of these enzymes, adenosine nucleosidase, was purified 5 days after germination period. The purification scheme consisted of ammonium sulfate precipitation, ion exchange chromatography, size exclusion, and aminohexyl chromatography. The enzyme was then characterized with regard to its isoelectric point and subunit molecular weight. Adenosine nucleosidase from soybean seeds was determined to most likely be a multimeric enzyme with a subunit molecular weight of approximately 18,000 Da based on SDS-PAGE.

The specific activity of the initial extract was 16 x 10<super>-2</super> mol/min mg. After increasing the ammonium sulfate to 60% and dialyzing the resulting precipitate, the specific activity increased to 62 x 10<super>-2</super> mol/min mg. The specific activity of adenosine nucleosidase increased to 2.44mol/min mg after the final column purification step. The purification fold and percent recovery for adenosine nucleosidase is 14.79 and 0.38%, respectively.

The isoelectric point of the enzyme was determined using an OFFGEL electrophoresis fractionator and found to be approximately 1.5.