Coordination complexes and catalytic properties of proteins and related substances. 105. Electrostatic effects in hemoglobin: Bohr effect and ionic strength dependence of individual groups

Biochemistry ◽  
1979 ◽  
Vol 18 (10) ◽  
pp. 1928-1936 ◽  
Author(s):  
James B. Matthew ◽  
George I. H. Hanania ◽  
Frank R. N. Gurd
Keyword(s):  
Ionic Strength ◽  
Catalytic Properties ◽  
Coordination Complexes ◽  
Bohr Effect ◽  
Electrostatic Effects ◽  
Ionic Strength Dependence ◽  
Related Substances ◽  
Strength Dependence

The ionic strength dependence of chromatin folding

1978 ◽  
Vol 36 (2) ◽  
pp. 220-221
Author(s):  
F. Thoma ◽  
TH. Koller
Keyword(s):  
Electron Microscopy ◽  
Electron Microscope ◽  
Ionic Strength ◽  
Specimen Preparation ◽  
Preparation Technique ◽  
Carbon Supports ◽  
Ionic Strength Dependence ◽  
Chromatin Folding ◽  
Strength Dependence ◽  
Preparation Techniques

Under a variety of electron microscope specimen preparation techniques different forms of chromatin appearance can be distinguished: beads-on-a-string, a 100 Å nucleofilament, a 250 Å fiber and a compact 300 to 500 Å fiber.Using a standardized specimen preparation technique we wanted to find out whether there is any relation between these different forms of chromatin or not. We show that with increasing ionic strength a chromatin fiber consisting of a row of nucleo- somes progressively folds up into a solenoid-like structure with a diameter of about 300 Å.For the preparation of chromatin for electron microscopy the avoidance of stretching artifacts during adsorption to the carbon supports is of utmost importance. The samples are fixed with 0.1% glutaraldehyde at 4°C for at least 12 hrs. The material was usually examined between 24 and 48 hrs after the onset of fixation.

Meso tetrakis ortho-, meta-, and para-N-alkylpyridiniopor-phyrins: kinetics of copper(II) and zinc(II) incorporation and zinc porphyrin demetalation

2003 ◽  
Vol 07 (03) ◽  
pp. 139-146 ◽  
Author(s):  
Peter Hambright ◽  
Ines Batinić-Haberle ◽  
Ivan Spasojević
Keyword(s):  
Aqueous Solution ◽  
Ionic Strength ◽  
Effective Charge ◽  
Methyl Ethyl ◽  
Ionic Strength Dependence ◽  
Zinc Porphyrin ◽  
Cationic Porphyrin ◽  
Strength Dependence ◽  
Acid Catalyzed ◽  
Kinetics Of

The relative reactivities of the tetrakis( N -alkylpyridinium- X - yl )-porphyrins where X = 4 (alkyl = methyl, ethyl, n -propyl) , X = 3 (methyl) , and X = 2 (methyl, ethyl, n -propyl, n -butyl, n -hexyl, n -octyl) were studied in aqueous solution. From the ionic strength dependence of the metalation rate constants, the effective charge of a particular cationic porphyrin was usually larger when copper(II) rather than zinc(II) was the reactant. The kinetics of ZnOH + incorporation and the acid catalyzed removal of zinc from the porphyrins in 1.0 M HCl were also studied. In general, the more basic 4- (para-) and 3- (meta-) isomers were the most reactive, followed by the less basic 2- (ortho-) methyl to n -butyl derivatives, with the lipophilic ortho n -hexyl and n -octyl porphyrins the least reactive.

Ionic Strength Dependence of Protonation Constants ofN-Alkyl Substituted Open Chain Diamines in NaClaq

2004 ◽  
Vol 49 (1) ◽  
pp. 109-115 ◽  
Author(s):  
Francesco Crea ◽  
Concetta De Stefano ◽  
Ottavia Giuffrè ◽  
Silvio Sammartano
Keyword(s):  
Ionic Strength ◽  
Protonation Constants ◽  
Ionic Strength Dependence ◽  
Open Chain ◽  
Strength Dependence

Coördination Complexes and Catalytic Properties of Proteins and Related Substances. II. The Reactivity of Carbobenzoxy-L-prolyl-L-histidylglycinamide1

1959 ◽  
Vol 81 (2) ◽  
pp. 295-301 ◽  
Author(s):  
Walter L. Koltun ◽  
Richard E. Clark ◽  
Richard N. Dexter ◽  
Panayotis G. Katsoyannis ◽  
Frank R. N. Gurd
Keyword(s):  
Catalytic Properties ◽  
Coordination Complexes ◽  
Related Substances
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