Open AccessPurification and Specificity of Aspergillus sojae DNase
Author(s) -
SUZUKI Masaru,
SAKAGUCHI Kenji
Publication year - 1974
Publication title -
european journal of biochemistry
Language(s) - English
Resource type - Journals
eISSN - 1432-1033
pISSN - 0014-2956
DOI - 10.1111/j.1432-1033.1974.tb03865.x
Subject(s) - phosphodiester bond , sephadex , enzyme , biochemistry , dna , nucleotide , chemistry , hydrolysis , deoxyribonuclease , polyacrylamide gel electrophoresis , deoxyribonucleases , biology , rna , gene
An endo‐type deoxyribonuclease isolated from autolysate of Aspergillus sojae was purified 175‐fold. The purified enzyme migrated as a single band during electrophoresis on polyacrylamide gel and hydrolysed only deoxyribonucleic acids. Optimal hydrolysis of DNA by the enzyme was observed at pH 9.4. The enzyme was strongly activated by Mg 2+ . Mn 2+ and Zn 2+ also enhanced the enzymatic activity, but to a lesser extent. Heat‐denatured DNA was found to be a better substrate than native DNA. The molecular weight of the enzyme determined by gel filtration on Sephadex G‐100 was 15600. A limited amount of the enzyme preferentially splits the phosphodiester bonds of purine nucleotides in DNA. The mononucleotides liberated are P ‐5′‐dGuo (major) and P ‐5′‐dAdo (minor). The oligonucleotides are terminated mostly either with P ‐5′‐dGuo or P ‐5′‐dAdo and partly with P ‐5′‐dCyd at the 5′‐phosphate termini, and with P ‐5′‐dGuo and P ‐5′‐dAdo at the 3′‐hydroxyl termini, respectively.