Xanthurenic acid and its rôle in the trytophane metabolism of pyroxidine-deficient rats

In a previous publication (1) the isolation of a green pigment from the urine of pyridoxine-deficient rats was described. The green pigment was shown to be the product of a reaction between ferric ammonium sulfate or other ferric salts and a compound whose nature was unknown. This compound has now been isolated in crystalline form. It is a yellow pigment and has been identified as xanthurenic acid

Nitrogen distribution by globin

This and other experiences with the tryptophane method of Fürth and Nobel led us to doubt seriously the reliability of quantitative data obtained by its application. When, therefore, just as we completed our work with it, Folin and Looney (6) described another and apparently better method of determination, a method based upon a different color reaction and capable moreover of convenient combination with a quantitative procedure for tyrosine, it seemed to us worth while to review the problem again. With the aid of this newer method we have now determined the tryptophane and tyrosine content of two series of globin preparations, and have, we believe, settled fairly decisively the proportion of these amino-acids yielded by the pure protein. We have also taken occasion to determine by the method of Van Slyke the general distribution of nitrogen in the globin molecule

The Production of Kynurenic Acid from Tryptophane and Indole Derivatives

The production of kynurenic acid from derivatives closely related to tryptophane serves as a means of indicating whether the animal organism is able to accomplish the changes necessary to convert such derivatives into tryptophane itself, or into some product intermediate in the transformation of tryptophane to kynurertic acid. With this in mind, a number of l-tryptophane and indole derivatives were prepared and administered to rabbits, both per os and subcutaneously, in amounts molecularly equivalent to 1 gm. of tryptophane and the kynurenic acid produced was estimated

The Availability of Tryptophane Derivatives for Supplementing Diets Deficient in Tryptophane

The utilization of tryptophane for growth in the rat can be effectively prevented by benzoylation, but not by acetylation or by esterification with ethyl alcohol. For the purpose of extending these observations, the phenylacetyl, phenylpropionyl, and propionyl derivatives of tryptophane, as well as the phenyl and benzyl ester hydrochlorides, were prepared and fed as supplements in a diet deficient in tryptophane. Of these derivatives, only phenylacetyltryptophane failed to produce growth. Presumably all of the others undergo enzymatic cleavage and hence can be utilized as well as free tryptophane for purposes of growth

Independent components in spectroscopic analysis of complex mixtures

We applied two methods of "blind" spectral decomposition (MILCA and SNICA) to quantitative and qualitative analysis of UV absorption spectra of several non-trivial mixture types. Both methods use the concept of statistical independence and aim at the reconstruction of minimally dependent components from a linear mixture. We examined mixtures of major ecotoxicants (aromatic and polyaromatic hydrocarbons), amino acids and complex mixtures of vitamins in a veterinary drug. Both MICLA and SNICA were able to recover concentrations and individual spectra with minimal errors comparable with instrumental noise. In most cases their performance was similar to or better than that of other chemometric methods such as MCR-ALS, SIMPLISMA, RADICAL, JADE and FastICA. These results suggest that the ICA methods used in this study are suitable for real life applications. Data used in this paper along with simple matlab codes to reproduce paper figures can be found at http://www.klab.caltech.edu/~kraskov/MILCA/spectraComment: 22 pages, 4 tables, 6 figure

A deseeded Avena test method for small amounts of auxin and auxin precursors

In 1927 Went isolated the growth promoting hormone, auxin, from the tip of the Arena coleoptile, and worked out the now well known Arena test method for its quantitative determination. By the use of this method the chemistry and many phases of the physiological action of auxin have been studied. In physiological work, however, the amounts of hormone involved are frequently so small that quantitative or even qualitative work has often been very difficult or impossible. In this article is presented a supplementary procedure with deseeded Arena seedlings whereby smaller concentrations of the hormone not detectable by the standard method can be quantitatively determined. By the use of this method it has also been possible to demonstrate directly the existence of substances capable of being converted into auxin by the plant. Some data relative to the presence of a precursor of auxin in Arena and synthetic precursors of hereto-auxin are included

The Influence of l- and dl-Tryptophane and Kynurenic Acid Administration on Bile Volume and Composition

We have undertaken to determine whether kynurenic acid production or excretion in the bile (as reported by Kotake and Ichihara) might be responsible, at least in part, for the choleretic effect of tryptophane. We have also studied the influence of optical configuration of tryptophane on bile volume and on bile salt output, both of which Whipple and Smith found were increased by l-tryptophane administration

Resolution of the clinical features of tyrosinemia following orthotopic liver transplantation for hepatoma

The clinical history before transplantation and subsequent clinical and biochemical course of 3 children and one adult with hereditary tyrosinemia treated by orthotopic hepatic transplantation is described. All four patients are now free of their previous dietary restrictions and appear to be cured of both their metabolic disease and their hepatic neoplasm. © 1986 Elsevier Science Publishers B.V. All rights reserved

On the plant growth hormone produced by Rhizopus suinus

Since it was first discovered that cell elongation in the Avena coleoptile is controlled by a hormone, our understanding of the nature and rôle of this substance has progressed considerably. Apart from the elucidation of its functions in promoting growth, tropisms, and other reactions of the plant, the chemical nature of the substance has been extensively studied. The active substance produced by cultures of the mold Rhizopus suinus was shown by Nielsen (1930) to be ether-soluble, and by Dolk and Thimann (1932) to be an unsaturated organic acid, decomposed by strong acids but not by alkalies, and readily inactivated by oxidation. Its dissociation constant, as measured by Dolk and Thimann, is 10^-4.75. Previously, Went (1928) had shown the molecular weight of the active substance in Avena coleoptiles to be about 376. The active substance in human urine was isolated by Kögl and Haagen-Smit (1931) and by Kögl, Haagen-Smit, and Erxleben (1933), and shown to be an acid, C17H28O(OH)COOH (auxin A), whose lactone is also active, while from malt these workers later isolated (1933) a ketohydroxy acid, C17H28O(OH)COOH (auxin B), which had the same activity per unit weight. On account of the rather small amount of substance available from Rhizopus cultures, and also since the bulk of the partially purified product was lost through spontaneous inactivation (see section, “Concluding stages”), the chemical investigation of the active substance, begun earlier, was dropped. However, the many experiments on purification which had meanwhile been carried out showed that the active substance from Rhizopus did not behave in quite the same way as that from urine. Recently, however, it was shown by Kögl, Erxleben, and Haagen-Smit (1934) that there is in urine a second active substance, identical with β-indolylacetic acid, and Kögl and Kostermans (1934) showed that the molecular weight of the substance produced by Aspergillus and by Rhizopus is that of β-indolylacetic acid rather than that of the C18 compounds. Since preparations from Rhixopus have been extensively used for physiological work, both in this laboratory and elsewhere, the exact nature of the active substance is of considerable interest. The present paper will give evidence that the active substance produced by Rhizopus suinus is in fact β-indolylacetic acid. Identification by the preparation of derivatives and by mixed melting points with the pure synthetic substance was not possible on account of the small amount of material available. Nevertheless, the evidence given below is fairly conclusive. The method of purification, since it differs to some extent from that adopted by Kögl and his coworkers, will also be outlined. Finally, it will be shown that some of the peculiar conditions previously found to be necessary for the production of this growth substance (Thimann and Dolk, 1933) find a simple explanation on this basis