IT SEEMS DESIRABLE TO EMPHASIZE THE FOLLOWING CONCLUSIONS: 1. A careful balancing of the normal acids and bases of the urine makes it possible not merely to detect the presence of organic acids in the urine, but also to determine approximately the amount of such acids. The method recently described by Herter and Wakeman can be recommended as securing a greater degree of accuracy, for the amount...

1. It may be shown by means of cells of the flowers of a hybrid Rhododendron which contain a natural indicator, by means of starfish eggs stained with neutral red, and by means of an "artificial cell" in which living frog's skin is employed that increased intracellular alkalinity may be brought about by solutions of a decidedly acid reaction which contain ammonium salts. 2. These results are an...

SINGLE CRYSTALS OF THE NEW TITLE COMPOUND [SYSTEMATIC NAME: 1,4,7,10-tetra-zoniadecane hexa-chloridorhodate(III) chloride], [H(3)N(CH(2))(2)NH(2)(CH(2))(2)NH(2)(CH(2))(2)NH(3)][RhCl(6)]Cl, were obtained from the corresponding amine and rhodium trichloride in hydro-chloric acid solution by slow crystallization under diffusion-controlled conditions at room temperature. Its solid-state structure i...

Chemical reactivity is observed following electron irradiation of a binary mixture of ammonia (NH(3)) and acetic acid (CH(3)COOD) at 25 K, without any subsequent thermal activation, as evidenced by vibrational high resolution electron energy loss spectroscopy (HREELS). Analysis of the HREEL spectra and comparison with infrared and Raman data of different molecules are compatible with glycine fo...

Four proteins active in blood coagulation have long been known to require vitamin K for their proper biosynthesis: factors II, VII, IX, and X. This paper describes the purification of a hitherto unrecognized vitamin K-dependent glycoprotein from bovine plasma. The biosynthesis of this protein is interfered with by the vitamin K antagonist Dicoumarol. The molecular weight of the protein is appro...

The NH(2)-terminal amino acid sequences of the alpha and beta chains of avian myeloblastosis alphabeta DNA polymerase were determined by using microsequence analysis in the subnanomole range and were found to be identical up to 17 residues. The common sequence was as follows: Thr-Val-Ala-Leu-His-Leu-Ala-Ile-Pro-Leu-Lys-Trp-Lys-Pro-Asn-His-Thr-. This result provides convincing chemical evidence ...

Escherichia coli ribonucleotide reductase is an α2β2 complex and catalyzes the conversion of nucleoside 5'-diphosphates (NDPs) to 2'-deoxynucleotides (dNDPs). The reaction is initiated by the transient oxidation of an active-site cysteine (C(439)) in α2 by a stable diferric tyrosyl radical (Y(122)•) cofactor in β2. This oxidation occurs by a mechanism of long-range proton-coupled electron trans...

Across many environments, nitrate (NO_3(-)) is an important form of N available for microorganisms and photosynthetic organisms. Accurate NO_3(-) measurements are important for examining N cycling and retention in terrestrial and aquatic ecosystems, but a common method of NO_3(-)) analysis can underestimate NO_3(-)) concentrations when soluble iron is present (iron > 10 mg L(-1)). The basic met...

NH+4 ions, at a concentration (0.25 mM) similar to that found in the plasma of patients with hepatic encephalopathy, cause, in vitro, a significant stimulation of the uptake by brain microvessels of large neutral amino acids, without any effect on the uptake of alpha-methylaminoisobutyric acid, glutamic acid, or lysine. Such a stimulation occurs essentially through an increase of the maximal tr...

Total mercury (Hg(T)) determination requires the addition of concentrated hydrochloric acid solution (≥10 mol L(-1) HCl) in relatively high amounts to preserve the samples and to prepare reagent solutions. A method for the preparation of concentrated HCl with Hg(T) concentration of lower than 5 ng L(-1) is described in this article. It is based on the well-known chemical reaction: 2 NH(4)Cl + H...