Open AccessDeoxyribonucleic Acid Polymerase from Physarum polycephalum
Author(s) -
BAER Anton,
SCHIEBEL Winfried
Publication year - 1978
Publication title -
european journal of biochemistry
Language(s) - English
Resource type - Journals
eISSN - 1432-1033
pISSN - 0014-2956
DOI - 10.1111/j.1432-1033.1978.tb12286.x
Subject(s) - physarum polycephalum , physarum , dna , polymerase , dna polymerase , sephadex , enzyme , biochemistry , microbiology and biotechnology , dna clamp , chemistry , biophysics , biology , polymerase chain reaction , reverse transcriptase , gene
DNA polymerase was purified 1000‐fold from the cytoplasm of microplasmodia of the myxomycete Physarum polycephalum. The activity was found in two forms exhibiting molecular weights of 204000 and 116000 respectively. Both forms eluted together from DNA‐cellulose and DEAE‐Sephadex columns. The Stokes radii were 6.5 and 5.5 nm. The sedimentation coefficients were 7.6 and 5.2 S. The frictional ratios of 1.69 suggest a highly hydrated and/or an asymmetric structure of the molecule. The enzyme‐catalyzed reaction was sensitive to N ‐ethylmaleimide (60% inhibition by 1 mM). Unlike DNA polymerase α from mammalian cells the Physarum enzyme was stimulated by 30 mM NaCl. Activated DNA was the preferred template. Poly(A) · (dT) 12 was not accepted. The K m value for deoxynucleoside triphosphates was 3 μM, for activated DNA 50 μg/ml and for Mg 2+ at the optimum [K + ] of 150 mM about 0.6 mM.