Archives of Biochemistry and Biophysics 

About: Archives of Biochemistry and Biophysics is an academic journal. The journal publishes majorly in the area(s): Enzyme & Amino acid. It has an ISSN identifier of 0003-9861. Over the lifetime, 32052 publication(s) have been published receiving 1176311 citation(s). The journal is also known as: Arch Biochem Biophys & Arch. Biochem. Biophys..

Tissue sulfhydryl groups

Abstract: A water-soluble (at pH 8) aromatic disulfide [5,5′-dithiobis(2-nitrobenzoic acid)] has been synthesized and shown to be useful for determination of sulfhydryl groups. Several applications have been made to show its usefulness for biological materials. A study of the reaction of this disulfide with blood has produced some evidence for the splitting of disulfide bonds by reduced heme.

Photoperoxidation in isolated chloroplasts. I. Kinetics and stoichiometry of fatty acid peroxidation.

Abstract: A photo-induced cyclic peroxidation in isolated chloroplasts is described In an osmotic buffered medium, chloroplasts upon illumination produce malondialdehyde (MDA)—a decomposition product of tri-unsaturated fatty acid hydroperoxides—bleach endogenous chlorophyll, and consume oxygen These processes show ( a ) no reaction in the absence of illumination; ( b ) an initial lag phase upon illumination of 10–20 minutes duration; ( c ) a linear phase in which the rate is proportional to the square root of the light intensity; ( d ) cessation of reaction occurring within 3 minutes after illumination ceases; and ( e ) a termination phase after several hours of illumination The kinetics of the above processes fit a cyclic peroxidation equation with velocity coefficients near those for chemical peroxidation The stoichiometry of MDA/O 2 = 002, and O 2 Chl bleached = 69 correlates well with MDA production efficiency in other biological systems and with the molar ratio of unsaturated fatty acids to chlorophyll The energies of activation for the lag and linear phases are 17 and 0 kcal/mole, respectively, the same as that for autoxidation During the linear phase of oxygen uptake the dependence upon temperature and O 2 concentration indicates that during the reaction, oxygen tension at the site of peroxidation is 100-fold lower than in the aqueous phase It is concluded that isolated chloroplasts upon illumination can undergo a cyclic peroxidation initiated by the light absorbed by chlorophyll Photoperoxidation results in a destruction of the chlorophyll and tri-unsaturated fatty acids of the chloroplast membranes

The preparation and chemical characteristics of hemoglobin-free ghosts of human erythrocytes

Abstract: The effects of the ionic strength and pH of the hemolyzing solution on the hemoglobin content of human erythrocyte ghosts were studied in phosphate buffers and found to have a pronounced influence upon hemoglobin binding in the ghosts. Buffer concentrations between 10 and 20 ideal milliosmolar (imOsm), at pH values 5.8 – 8.0, resulted in maximum hemoglobin removal from ghosts. The pH optimum for hemoglobin binding to ghosts was between 5.8 and 5.9 in a 20 imOsm buffer. The influence of these variables suggest an electrophysical interaction of hemoglobin with membrane constituents. This study provides a basis for comparison of existing methods for ghost preparation, as well as a means for prediction of the conditions required for preparation of ghosts containing any desired amount of hemoglobin. Conditions were found that allowed the preparation of hemoglobin-free ghosts by single-stage hemolysis and washing. Hemoglobin-free ghosts were prepared in 20 imOsm phosphate buffer at pH 7.4. Essentially all the lipid was recovered in the ghosts, but non-hemoglobin nitrogen-containing substances were lost. The pyridine hemochromogen method for hemoglobin determination was adapted for the measurement of very small quantities of hemoglobin through use of the Soret band (418 mμ) for absorbancy measurements.

The determination of hydroxyproline in tissue and protein samples containing small proportions of this imino acid.

Abstract: A method is presented for the quantitative determination of hydroxyproline in biological materials containing as little as one part of hydroxyproline in 4000 parts of amino acids. Thus method has been applied to a study of hydroxyproline distribution in cell particulates, tissue fluids, and purified plant and animal proteins. Significant amounts of hydroxyproline were found in crystalline preparations of pepsin, elastase. and ficin.

The preparation and properties of two new chromogenic substrates of trypsin.

Abstract: The synthesis and properties of l -lysine p -nitroanilide dihydrobromide and benzoyl dl -arginine p -nitroanilide hydrochloride are described. Both compounds are hydrolyzed by trypsin, the latter being a substrate at least as sensitive as benzoyl l -argininamide. Their hydrolysis can be followed conveniently by colorimetric procedures, since one of the products, p -nitroaniline, is yellow. Values of K m and k 3 for their reaction with trypsin were determined, as well as the K 4 of benzoyl d -arginine p -nitroanilide, which was isolated from a tryptic digest of the dl isomer. The pH-activity curves were also determined, that of l -LPA being in a more alkaline region than normally found for trypsin substrates. The possible significance of this shift is discussed. Preliminary studies indicate that benzoyl dl -arginine p -nitroanilide hydrochloride is also hydrolyzed by papain.