A micromethod for the determination of arginine

Micromethods for the determination of arginine based on the use of the Sakaguchi reagent have been described (14). This reagent gives a strong color with glycocyamine, arginine, and other monosubstituted guanidine derivatives. In a previous communication (5) a method for the determination of glycocyamine was described based on the Sakaguchi reaction and the quantitative separation of glycocyamine from arginine by selective adsorption of the arginine on permutit. In the method outlined below the separated arginine is eluted from the permutit and determined independently

Some elementary observations regarding reductive Cartan geometries

After defining generalizations of the notions of covariant derivatives and geodesics from Riemannian geometry for reductive Cartan geometries in general, various results for reductive Cartan geometries analogous to important elementary results from Riemannian geometry are proven using these generalizations. In particular, a generalization of the Hopf-Rinow theorem is given with a pleasantly concise proof.Comment: 8 pages, no figure

The conversion of citrulline to arginine in kidney

Glycocyamine is formed in the kidney by the transfer of the amidine group of arginine to the nitrogen atom of glycine. In the study of this reaction it was observed that glycocyamine was also formed from citrulline and glycine. No other donor or precursor of the amidine group was found (1)

Synthesis of hippuric acid in liver homogenate

The synthesis of hippuric acid from benaoic acid and glycine resembles in several respects the synthesis of a peptide bond. A CONH group is formed, it is a to a carboxyl group, and the free energy of its formation is of the same order of magnitude. The synthesis was demonstrated in liver and kidney slices of a number of animals; it is inhibited by 0.001 M KCN, which is in accord with the view that the necessary free energy is derived from an oxidation.(1

Methylation of guanidoacetic acid by homocystine plus choline with rat liver slices

The methylation of guanidoacetic acid by liver slices is accelerated by methionine; choline, under these conditions, exerts no significant accelerating effect (1). In view of the fact that homocystine plus choline can replace methionine for growth (2), and of the isotope experiments which proved the transfer in viva of the methyl groups of choline to creatine,(3) it has been suggested, from indirect evidence, that the pathway of the methyl group to creatine is more direct from methionine than from choline.(4) More specific evidence is desirable, especially as neither homocystine nor homocysteine has been identified in animal tissues

Dimethylthetin and dimethyl-β-propriothetin in methionine synthesis

In a previous communication it was shown that choline and betaine are effective in promoting methionine synthesis from homocysteine in tissue homogenates (1). Data presented in this paper indicate that dimethylthetin, (CH3)2+SCH2COO-, which has been shown by Welch (2) to be lipotropic and has been reported by du Vigneaud (3) to promote growth on a methionine-free, homocysteine-containing diet, is 20 times as active as betaine in methionine formation. Dimethyl-β-propiothetin, (CH3)2+S(CH2)2COO-, recently isolated from Polysiphonia fastigiata by Challenger and Simpson (4) is also highly active. The enzyme for this transmethylation is found in the liver and kidney of all animals tested. Its high activity and general distribution suggest its biological importance in methionine synthesis

Classifying Families of Character Degree Graphs of Solvable Groups

We investigate prime character degree graphs of solvable groups. In particular, we consider a family of graphs $\Gamma_{k,t}$ constructed by adjoining edges between two complete graphs in a one-to-one fashion. In this paper we determine completely which graphs $\Gamma_{k,t}$ occur as the prime character degree graph of a solvable group.Comment: 7 pages, 5 figures, updated version is reorganize