scholarly journals Partial purification of deoxyribonucleic acid polymerase from Mycobacterium smegmatis

1968 ◽  
Vol 110 (2) ◽  
pp. 10P
Author(s):  
F G A Winder ◽  
M S McNulty ◽  
L A Callender
Keyword(s):  
Mycobacterium Smegmatis ◽  
Deoxyribonucleic Acid ◽  
Partial Purification

scholarly journals A nucleoside triphosphate-dependent deoxyribonucleic acid-breakdown system in Mycobacterium smegmatis, and the effect of iron limitation on the activity of this system

1969 ◽  
Vol 111 (5) ◽  
pp. 679-687 ◽  
Author(s):  
F. G. Winder ◽  
M. P. Coughlan
Keyword(s):  
Dna Content ◽  
Mycobacterium Smegmatis ◽  
Deoxyribonucleic Acid ◽  
Maximal Activity ◽  
Enzyme Concentration ◽  
Iron Limitation ◽  
Nucleoside Triphosphate ◽  
Primary Products ◽  
Rate Of Reaction ◽  
Optimum Ph

1. The presence of a nucleoside triphosphate-dependent DNA-breakdown system was demonstrated in extracts of Mycobacterium smegmatis. Its activity was increased substantially by iron limitation, apparently after the fall in DNA content that took place under these conditions. A maximal activity of about 0·2μmole of deoxyribonucleotide/30min./mg. of protein was found in crude extracts. 2. After slight purification by streptomycin treatment, the enzyme showed maximal activity with undenatured DNA (Km≃200μg./ml.), ATP (Km≃1·2mm) or UTP, CTP and GTP giving lower activity and pyrophosphate giving none, and Mg2+ ions (optimum concn. 12mm). The optimum pH was 8·5. 3. In the assay system there was proportionality between enzyme concentration and rate of reaction, but the rate fell off with time. 4. ATP was broken down in the reaction and monodeoxy-ribonucleotides were among the products, but the presence of some oligodeoxy-ribonucleotides was not excluded and the degree of phosphorylation of the primary products was uncertain.

scholarly journals The deoxyribonucleic acid polymerases from the diatom Cylindrotheca fusiformis. Partial purification and characterization of four distinct activities

1977 ◽  
Vol 167 (3) ◽  
pp. 601-610 ◽  
Author(s):  
T W Okita ◽  
B E Volcani
Keyword(s):  
Deoxyribonucleic Acid ◽  
Maximum Activity ◽  
Partial Purification ◽  
Purification And Characterization ◽  
Cylindrotheca Fusiformis ◽  
High K ◽  
Zinc Chelator ◽  
Relationship Of ◽  
The Relationship

Four extramitochondrial DNA polymerases from the marine photosynthetic diatom Cylindrotheca fusiformis were isolated and purified more than 1200-fold by chromatography on DNA-cellulose and DEAE-Sephadex. The enzymes were equally susceptible to inhibition by the thiol-blocking agents N-ethylmaleimide and p-chloromercuribenzoate, the zinc chelator o-phenathroline, and the nucleic acid interchelators ethidium bromide and acriflavin; they displayed similar pH optima, preferred activated DNA, and had strict dependence on high K+ for maximum activity. They were differentiated on the basis of their kinetic parameters, template-primer utilization and salt requirements. The four activities varied with growth stage of C. fusiformis. Activities of polymerases A and D doubled in exponential-phase cells as compared with those in stationary-phase cells, and the increase in polymerase B and chloroplast activity C was 20-40%. The relationship of the diatom polymerases to the complements in other organisms is discussed.

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