PubMed Health⌕ Search

Biomedical subjects

M Misumi

Publications and source records attributed to M Misumi.

31 records · Page 2Linked to original sources
PubMed1982

The isolation and characterization of DNA polymerase alpha from spinach.

A DNA polymerase with the characteristics of the alpha class of eukaryotic DNA polymerases has been purified 1000-fold from spinach leaves. The enzyme has a molecular weight of 160,000 +/- 10,000 in its native form and is markedly inhibited by aphidicolin and N-ethylmaleimide, but not by dideoxynucleoside triphosphates. As isolated, the enzyme contains no detectable deoxyribonuclease activity. A catalytically active 12-kilodalton fragment of the DNA polymerase, apparently generated by endogenous proteolytic action, has also been purified. The native enzyme is found predominantly in the cytoplasmic fraction of broken leaf cell preparations and less than 10% is found associated with the nuclei.

Cell Nucleus↗
PubMed1979

Mechanism of action of aclacinomycin A II. The interaction with DNA and with tubulin.

Aclacinomycin A was observed to effect the thermal denaturation of DNA and to increase Tm. The visible absorption spectrum of the antibiotic showed bathochromic and hypochromic shifts upon reaction with native and heat-denatured DNA. [14C]Aclacinomycin A was demonstrated by equilibrium dialysis to bind to DNA. Native calf thymus DNA appeared to possess one binding site per ca. 6 nucleotides for the antibiotic with an apparent association constant of ca. 1.2 x 10(6) M-1. Heat-denatured DNA showed much less affinity for the antibiotic: one binding site per ca. 6 nucleotides with an apparent binding constant of ca. 3.5 x 10(4) M-1. The difference of association constants between double- and single-stranded DNAs suggested that the antibiotic may be intercalated between base pairs of the DNA double helix. [14C]Aclacinomycin A exhibited higher affinity for poly(dAdT) than for poly(dIdC). The antibiotic showed a significant difference spectrum with porcine tubulin, indicating an interaction with tubulin. The binding to tubulin was also demontstrated by equilibrium dialysis of [14C]aclacinomycin A and tubulin.

Antibiotics, Antineoplastic↗