scholarly journals Deoxyribonucleic acid polymerases of Euglena gracilis. Purification and properties of two distinct deoxyribonucleic acid polymerases of high molecular weight

1975 ◽  
Vol 151 (2) ◽  
pp. 227-238 ◽  
Author(s):  
A G McLennan ◽  
H M Keir
Keyword(s):  
Molecular Weight ◽  
High Molecular Weight ◽  
Euglena Gracilis ◽  
Deoxyribonucleic Acid ◽  
Deae Cellulose ◽  
Low Molecular Weight ◽  
Optimum Conditions ◽  
Electrophoretic Mobilities ◽  
Substrate Activation ◽  
Purification And Properties

Two DNA polymerases of high molecular weight, pol A (mol.wt. 190 000) and pol B (mol.wt. 240 ooo), have been purified 6300-fold and 1600-fold respectively from an extramitochondrial supernatant of a bleached strain of Euglena gracilis. They have very similar requirements when assayed with an ‘activated’-DNA primer-template [the optimum conditions of pH and ionic (K+ and Mn2+) composition being 7.2, 25 mM and 0.2 mM respectively]. 0.2 mM-Mn2+ was about 1.5-2-fold as effective as 2 mM-Mg2+, owing to substrate activation by deoxyribonucleoside 5′-triphosphates in the presence of Mn2+. Km values for the triphosphates in the absence of activation were about 10(-6)M with Mn2+ and 8 × 10(-6) M with Mg2+ for both enzymes. They were inhibited to the same extent by N-ethylmaleimide, novobiocin and o-phenanthroline, but differed in their chromatographic behaviour on DEAE-cellulose and in their electrophoretic mobilities on polyacrylamide gel. No evidence was found for the existence in these cells of a DNA polymerase of low molecular weight, but there were indications that a third enzyme of high molecular weight might exist.

scholarly journals Deoxyribonucleic acid synthesis in mammalian systems. Permealysed Ehrlich ascites cells in vitro first label Okazaki-type low-molecular-weight deoxyribonucleic acid and then high-molecular-weight deoxyribonucleic acid

1972 ◽  
Vol 130 (4) ◽  
pp. 959-964 ◽  
Author(s):  
Leigh A. Burgoyne
Keyword(s):  
Molecular Weight ◽  
High Molecular Weight ◽  
Deoxyribonucleic Acid ◽  
Acid Synthesis ◽  
Preparation Procedure ◽  
Low Molecular Weight ◽  
Deoxyribonucleic Acid Synthesis ◽  
Ehrlich Ascites ◽  
Ehrlich Ascites Cells

During the evaluation of a method of preparing permealysed Ehrlich ascites cells, shortterm labelling experiments were carried out with d[3H]TTP. In the first minute the bulk of the label appeared as low-molecular-weight pieces of DNA. Subsequently the label appeared in DNA of much higher molecular weight. A brief description of the preparation procedure and the properties of the product is provided. Evidence is presented to show that the nucleotide was incorporated directly without intermediate conversion into dTMP or thymidine.

Purification and Properties of Rat α2 Acute-Phase Macroglobulin (α2M)

1979 ◽  
Author(s):  
W. Nieuwenhuizen ◽  
J. J. Emeis ◽  
J. Hemmink
Keyword(s):  
Molecular Weight ◽  
Acute Phase ◽  
Deae Cellulose ◽  
Rat Plasma ◽  
Low Molecular Weight ◽  
Purification Procedure ◽  
Purification And Properties ◽  
Purification Scheme ◽  
Pure Amino Acid ◽  
Proteolytic Activities

For our studies on the relation between blood fibrinolytic activity and repair of mechanically damaged arteries in our rat model we need a specific and sensitive assay for α2M. in the rat α2M is an acute-phase protein of which the level in blood is normally near zero but increases as a result of the damage. Moreover α2M is known to inhibit proteases involved in the fibrinolytic system. We developed a new purification procedure in which, conditions known to be harmful to the functionality of α2M were avoided. α2M was purified from plasma of turpentine-treated rats and proteolytic activities were suppressed throughout the purification procedure. The purification scheme successively involves: rivanol precipitation, Con A-Sepharose chromatography and DEAE-cellulose chromatography. Thus 48 mg of α2M was obtained from 100 ml rat plasma i.e. 20% recovery. The preparations were biochemically and immunologically pure. Amino acid and carbohydrate compositions were determined. The molecular weight is 760.000. The molecule consists of 4 subunits, M.W. = 190.000. A 1%1cm = 8.8 and p1 = 4.8. It binds 1 mole of trypsin or plasmin per mole. Bound proteases were only active on low molecular weight substrates such as BAEE and BOC-L-val-gly-L-arg βNA. Kinetic data of the bound enzymes (pH-optimas, Km and Vmax) indicate that factors other than steric hindrance are involved in the inhibitory action of α2M.

scholarly journals The Heterogeneity of the High Molecular Weight B12 Binder in Serum

Blood ◽  
1969 ◽  
Vol 33 (6) ◽  
pp. 899-908 ◽  
Author(s):  
CHRISTINE LAWRENCE
Keyword(s):  
Molecular Weight ◽  
Vitamin B12 ◽  
High Molecular Weight ◽  
Serum Proteins ◽  
Gel Filtration ◽  
Deae Cellulose ◽  
Weight Fraction ◽  
Low Molecular Weight ◽  
Transcobalamin I ◽  
Transcobalamin Ii

Abstract The binding of vitamin B12 by serum proteins was studied by separating Co57B12-enriched serum by Sephadex gel filtration, column chromatography with DEAE-cellulose, and paper electrophoresis. Each method of separation yielded two discrete B12-binding fractions. However, the analysis of each serum by all three separation technics indicated that one of the fractions was, in each case, bipartite. The "high" molecular weight B12-binding fraction defined by Sephadex gel filtration consisted of transcobalamin I and just part of the transcobalamin II fraction. The remaining portion of transcobalamin II was eluted from Sephadex gel in a "low" molecular weight fraction. Thus, transcobalamin II, equivalent to the β-globulin B12-binder, consisted of both "high" and "low" molecular weight components. This suggests that there are at least three serum proteins that can bind vitamin B12: two β-globulins, together comprising the transcobalamin II fraction and differing in molecular weight; and transcobalamin I.

scholarly journals Deoxyribonucleic acid polymerases of Euglena gracilis. Primer-template utilization of and enzyme activities associated with the two deoxyribonucleic acid polymerases of high molecular weight

1975 ◽  
Vol 151 (2) ◽  
pp. 239-247 ◽  
Author(s):  
A G McLennan ◽  
H M Keir
Keyword(s):  
Molecular Weight ◽  
High Molecular Weight ◽  
Euglena Gracilis ◽  
Enzyme Activities ◽  
Deoxyribonucleic Acid ◽  
Dna Polymerases ◽  
Tetrahymena Pyriformis ◽  
Nuclease Activity ◽  
Alkaline Ph ◽  
High Molecular Weight Dna

The two high-molecular-weight DNA polymerases from Euglena gracilis, pol A (mol. wt. 190 000) and pol B (mol. wt. 240 000), were differentiated on the basis of associated enzymic activities and primer-template utilization. Neither enzyme had endodeoxyribonuclease activity, but pol B, like pol B of yeast and the corresponding enzyme from Tetrahymena pyriformis, exhibited at least one other nuclease activity directed against denatured DNA and the RNA of an RNA-DNA hybrid. These nuclease functions preferred an alkaline pH and Mg2+. Pol B also exhibited nucleoside diphosphokinase activity. Both enzymes were active with ‘activated’ DNA and poly[d(A-T)] as primer-templates and were sensitive, especially pol B, to inhibition by excess of native or heat-denatured DNA. Pol B also utilized oligo[d(T)] and poly(A) templates under certain conditions, whereas pol A exhibited only slight activity with poly[d(A)]. (U)6 was not used as a primer by either enzyme.

The Effect of Dextran of Various Molecular Weight on the Coagulation in Dogs

1961 ◽  
Vol 06 (01) ◽  
pp. 015-024 ◽  
Author(s):  
Sven Erik Bergentz ◽  
Oddvar Eiken ◽  
Inga Marie Nilsson
Keyword(s):  
Molecular Weight ◽  
Body Weight ◽  
High Molecular Weight ◽  
Bleeding Time ◽  
Factor Vii ◽  
Low Molecular Weight ◽  
Factor V ◽  
Coagulation Mechanism ◽  
Coagulation Defects

Summary1. Infusions of low molecular weight dextran (Mw = 42 000) to dogs in doses of 1—1.5 g per kg body weight did not produce any significant changes in the coagulation mechanism.2. Infusions of high molecular weight dextran (Mw = 1 000 000) to dogs in doses of 1—1.5 g per kg body weight produced severe defects in the coagulation mechanism, namely prolongation of bleeding time and coagulation time, thrombocytopenia, pathological prothrombin consumption, decrease of fibrinogen, prothrombin and factor VII, factor V and AHG.3. Heparin treatment of the dogs was found to prevent the decrease of fibrinogen, prothrombin and factor VII, and factor V otherwise occurring after injection of high molecular weight dextran. Thrombocytopenia was not prevented.4. In in vitro experiments an interaction between fibrinogen and dextran of high and low molecular weight was found to take place in systems comprising pure fibrinogen. No such interaction occurred in the presence of plasma.5. It is concluded that the coagulation defects induced by infusions of high molecular weight dextran are due to intravascular coagulation.

Research on Chemical Modification of Wood of Fast-Growing Poplar

2013 ◽  
Vol 749 ◽  
pp. 461-465
Author(s):  
De Jun Shen ◽  
Chang Hai Yu ◽  
Zhen Xing
Keyword(s):  
Mechanical Properties ◽  
Molecular Weight ◽  
Structural Material ◽  
Chemical Modification ◽  
Orthogonal Test ◽  
Low Molecular Weight ◽  
Wood Structure ◽  
Optimum Conditions ◽  
Fast Growing ◽  
Performance Requirements

This topic is considered to modify the fast-growing Poplar to improve the properties, in order to fully meet the performance requirements for the structural material. This study aims to improve the dimensional stability and some other mechanical properties through impregnated with the low-molecular-weight PF resin. Through design orthogonal test in different mole ratio of Formaldehyde and Phenol, different amount of NaOH and PVA, we make PF resin to impregnate Poplar and pressing into laminated timber to measure bonding strength, MOR, MOE. The study indicated that: the optimum conditions of the low molecular weight PF resin for modify Poplar are: mole ratio of Formaldehyde and Phenol is 2.4, mole ratio of NaOH and phenol is 0.05, amount of PVA is 3% of the phenol. Under this condition Poplar specimen got the biggest increase in various properties and it can satisfy the requirements of the outdoor wood structure.

scholarly journals Purification and properties of two extracellular β-lactamases from Bacillus cereus 569/H

1970 ◽  
Vol 118 (3) ◽  
pp. 457-465 ◽  
Author(s):  
S. Kuwabara
Keyword(s):  
Molecular Weight ◽  
Bacillus Cereus ◽  
Zinc Sulphate ◽  
Deae Cellulose ◽  
Casein Hydrolysate ◽  
Crystalline Form ◽  
Casamino Acid ◽  
Fractional Precipitation ◽  
Purification And Properties ◽  
Rapid Production

1. When Bacillus cereus 569/H was grown in a casamino acid (casein-hydrolysate) medium containing zinc sulphate rapid production of extracellular β-lactamase II preceded that of β-lactamase I. 2. β-Lactamase I was separated from β-lactamase II by fractional precipitation with ammonium sulphate. 3. β-Lactamase I was purified by a process involving chromatography on Celite and DEAE-cellulose and β-lactamase II by chromatography on DEAE-cellulose after denaturation of β-lactamase I by heat. Both enzymes were obtained in crystalline form. 4. β-Lactamase II prepared in this way appeared to have a higher molecular weight than β-lactamase I and required Zn2+ as a cofactor for both cephalosporinase and penicillinase activities.

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