We describe a method for recording oxygen dissociation curves for whole-blood specimens. The blood sample is placed in a thermostated measuring chamber, and Po2 and S02 are measured continuously by polarography and by reflectometry, respectively. During the recording of an oxygen dissociation curve, the po2 and S02 signals are stored in a data-acquisition system, while pH, Pco2 and temperature ...

1. The rate of hydrolysis at different pH values of glycyl glycine, glycyl leucine, glycyl alanine, glycyl asparagine, glycyl aspartic acid and biuret base has been determined. 2. The pH-activity curves obtained in this way differ for the different substrates. 3. The curves can be satisfactorily predicted by the assumption that erepsin is a weak acid or base with a dissociation constant of 10(-...

The rate and equilibrium constants for the formation and dissociation of the bovine ventricular (BV) actomyosin-S1-ADP have been measured by stopped flow light scattering. A comparison of the rate constants obtained here with those for rabbit skeletal (RS) actomyosin-S1 indicates that there are large differences in several of the rate and equilibrium constants. 1) The rate constant of ADP disso...

Intracellular free calcium concentration in the sea urchin egg was calculated to increase from 0.1 mM in an unfertilized egg to 1 mM in a fertilized egg 10 min after fertilization, based on measurement of the dissociation constant between free calcium and sea urchin egg homogenate. The dissociation constant between free calcium (dialyzable calcium) and homogenate of sea urchin eggs was measured...

Pepstatin, a strongly bound inhibitor of acid proteases, does not instantaneously bind to pepsin. The dissociation constant of pepsin-pepstatin complex is 9.7×10-11 M using Phe・Gly・His・Phe(NO2)・Phe・Ala・PheOMe as substrate. Difference ultraviolet absorption spectra show conformational change of pepsin in interaction with pepstatin. The bindillg of pepsin with pepstatin is stoicheometric and the ...

A circularly polarized luminescence (CPL) spectrometer has been built and used to study the binding interaction of lactate and four different proteins with racemic EuIII and TbIII complexes in aqueous solution. Lactate binding gives rise to strong induced CPL spectra, and the observed emission dissymmetry factors vary linearly with enantiomeric composition. Particularly strong induced TbIII CPL...

Humic acids extracted from different soils. The stability constants of metal humates and acid dissociation constant humic acids were calculated. Forms of metals in natural waters was determined with use account their chemical composition and content and properties of organic matter. We assessed metals speciation in water objects with account for competitive reactions resulting in formation of h...

Inhibition of recombinant D-amino acid oxidase from Trigonopsis variabilis (TvDAAO) activity in the presence of different sodium salts and potassium chloride is reported. A competitive inhibition pattern by sodium chloride was observed, and an inhibition constant value of K(i) = 85 mM was calculated. Direct connection of NaCl inhibition with FAD cofactor dissociation was confirmed by measuring ...

The pigeon liver fatty acid synthetase complex (s:~,~ = 14.0 S) is inactivated and dissociated into half-molecular weight subunits (s”,,,, = 9.0 S) in the presence of low ionic strength buffers. The rates of inactivation and dissociation of the complex are dependent upon the ionic strength, pH, and temperature of the medium. At low ionic strengths (0.01 or less) and mildly alkaline pH (8.35), t...