The Major Fraction of Deoxyribonuclease Activity from Human Urinary Proteins Purification and Properties

Summary: The major fraction of deoxyribonuclease activity from human urinary protein was purified 40-fold in about 14 % yield. The enzyme shows an isoelectric point at pH 4.2 and has a molecular weight of 33,600 ± 3,000. Optimum activity was shown at pH 6.8 in the presence of 12.5 mmol/1 Mg2 * plus 1 mmol/1 Ca2+. The enzymic reaction is inhibited by high ionic strength (> 300 mmol/1 Na+). The purified enzyme readily hydro-lyzes native DNA to oligodeoxyribonucleotides with an average chain length of 5.3 ± 0.2 after exhaustive digestion. Therefore, this endonuclease may be designated as neutral deoxyribonuclease (deoxyribonucleate oligonucleotido-hydrolase, EC 3.1.4.5). Die Desoxyribonuclease mit der höchsten Enzymaktivität aus menschlichem Harn: Reinigung und Eigenschaf te