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Gradation of specificity with regard to sugar among nucleases

1968; Elsevier BV; Volume: 30; Issue: 3 Linguagem: Inglês

10.1016/0006-291x(68)90453-1

1090-2104

William J. Wechter, Andrzej Mikulski, M. Laskowski,

Plant Virus Research Studies

This chapter discusses the purification and properties of the mung bean nuclease. Mung bean nuclease cleaves single-stranded DNA endonucleolytically to form 5'-P-terminated mono- and oligonucleotides ending predominantly in Y-OH A(60%) and 3'-OH T(30%). With an excess of enzyme a mixture of mononucleotides is obtained. The enzyme has no specificity with respect to the sugar moiety and hydrolyzes derivatives of deoxyribose, ribose, and arabinose. With native viral DNA as substrate mung bean nuclease inflicts a limited number of endonucleolytic cleavages at specific AT-rich sites. An assay particularly suitable for following the purification of mung bean nuclease depends on the liberation of acid-soluble material from denatured DNA. A solution of calf thymus or salmon sperm DNA (2 mg/ml) is dialyzed against a large volume of distilled water. This serves a dual purpose of denaturing DNA as well as removing an excess of salt often present in commercial preparations of DNA.