Showing papers in "Journal of Biological Chemistry in 1950"

TL;DR: A short and simple calorimetric method is here described that is applicable to the determination of hydroxyproline in hydrolysates of 40 to 100 y of collagen with a reproducibility of f2 per cent and an accuracy of f1 per cent as judged by recovery of hydroXYproline from elastin hydrolysate and from an amino acid mixture simulating collagen.

TL;DR: A simple method is described here for determining collagen in small amounts of tissue with a precision and accuracy usually better than f5 per cent and in tissues containing but little collagen much of the soluble protein is separated from the tissues with the aid of 20 per cent urea solution.

TL;DR: Another test which appears to be specific for 17,21-dihydroxy-20-ketosteroids is added, based upon the appearance of a yellow color in solutions containing the steroid, phenylhydrazine, and sulfuric acid.

TL;DR: An enzyme has now been purified from yeast and liver which catalyzes the reversible synthesis of DPN and PP according to equation (1), which shows that the production of inorganic pyrophosphate was not a result of simple hydrolysis of adenosine triphosphate (ATP).

TL;DR: The over-all reaction to kynurenine is described, and the first two steps are identified as a physiological, coupled oxidation system consisting of a tryptophan peroxidase and an oxidase which forms peroxide.

TL;DR: In the initial studies (5) it was found that a thermostable factor was required in the over-all Reactions II and III, which led eventually to the discovery and isolation of glucose diphosphate, which acts as a coenzyme in Reaction III.

TL;DR: Investigators found that TPN synthesis by an aqueous extract of pigeon liver acetone powder took place without added DPN, and adenylic acid replaced ATP, and nicotinamide originally present in the aqueously extract was completely converted to TPN.

TL;DR: The studies described in this report offer evidence pertinent to the problem of the biologic origin of bile pigment that glycine is specifically utilized in the biosynthesis of protoporphyrin and that the administration of N16-labeled glycine provides a method for the determination of the average life span and pattern of destruction of the human erythrocyte in normal and pathologic states.

TL;DR: The specific gravity measurements are carried out by letting drops of plasma or whole blood fall into a graded series of copper sulfate solutions of known specific gravities, and noting whether the drops rise or fall in the solutions.

TL;DR: Evidence is presented that mammalian tyrosinase prepared from the Harding-Passey mouse melanoma is an enzyme which requires copper for activity and that the addition of copper to such a preparation restores activity.