Venom exonuclease (Phosphodiesterase I) successively hydrolyzes 5'-mononucleotides from 3'-OH-terminated ribo- and deoxyribo-oligonucleotides. The enzyme has an optimal pH range of 9.8-10.4 and a molecular weight of 115 kDa. Phosphodiesterase is inhibited by reducing agents such as glutathione, cysteine and ascorbic acids. It is completely inhibited by 5mM EDTA while ATP, ADP and AMP are partial inhibitors. The enzyme has an absolute requirement for Mg2 .
Phosphodiesterase I breaks phosphodiester bonds and catalyzes the hydrolysis of various nucleotide polyphosphates. Phosphodiesterase I is released from eucaryotic plasma membranes by phosphatidylinositol-specific phospholipase C.
Purified by the method of Williams, Sung and Laskowski, JBC, 236, 1130 (1961). Further treated to inactivate contaminating 5'-nucleotidase activity according to Sulkowski and Laskowski: BBA, 240, 443 (1961). Lyophilized in vials.
Phosphodiesterase (PDE) is any enzyme that is used to breaks phosphodiester bonds. It is a membrane-bound glycoprotein that is used to catalyze the hydrolysis of various nucleotide polyphosphates. Phosphodiesterase I is used in phosphodiesterase activation assays to hydrolyze AMP.