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KMID : 0380219930260050433
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Journal of Biochemistry and Molecular Biology
1993 Volume.26 No. 5 p.433 ~ p.439
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Purification and Properties of 5'-Deoxy-5'-Methylthioadenosine Phosphorylase from Rat Spleen
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Sung Ho Lee and Young Dong Cho
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Abstract
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5`-Deoxy-5`-methylthioadenosine (MTA) phosphorylase (EC 2.4.2.28) was purified to homogeneity from rat spleen by procedures involving heat treatment and Blue-Sepharose CL-4B chromatography as the major steps. The MTA phosphorylase had a native molecular weight of 64,000 daltons and consisted of two identical subunits, as estimated by gel filtration and SDS polyacrylamide gel electrophoresis. The phosphorylase exhibited high specificity towards a natural substrate with a K_m value of 1.0×10^8 M for MTA. It did not cleave adenine from S-adenosylhomocysteine. Optimum pH and temperature were 7.2 and 70℃, respectively. The activation energy calculated by Arrhenius equation was 9 ㎉/㏖. The enzyme showed a high degree of thermal stability and a requirment for -SH reducing agents, and was specifically inactivated by thiol-blocking compounds. Polyamines (putrescine, spermidine, and spermine) at 100 μM concentration increased enzyme activity up to 30∼40% of control activity. Because of this enhanced enzymatic activity due to polyamine, MTA might be effectively removed.
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KEYWORD
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