The work to be presented in this thesis concerns the divergent pathways of tryptophan metabolism to the 5-hydroxyindoles and to kynurenine. More specifically an attempt has been made to elucidate the role of dietary tryptophan in the operation of these two pathways. Previous investigators have implied that thiamine is involved in the kynurenine-forming pathway. Both nutritional studies and experiments in vitro were carried out to determine just where thiamine (or thiamine pyrophosphate, its coenzyme form) exerts its action.

The nitrification of ammonia and nitrite in soil is but one part of the overall nitrogen cycle. Essentially, nitrification may be defined as an oxidative-reductive mechanism whereby ammonium ions or nitrite ions are oxidized to nitrate by microorganisms.

At the outbreak of World War II, work was initiated in the Department of Biochemistry at McGill University, under the direction of Dr. O. F. Denstedt, on a study of the means whereby the then existing methods of blood preservation might be improved. Similar investigations were undertaken in many other laboratories throughout the world, particularly in the United States and Great Britain. The availability of blood and plasma for prompt treatment of the wounded at the fighting front accounted for the tremendous saving of lives in World War II as compared with World War I.

The literature on the enzyme tyrosinase is extensive and to a large extent contradictory. No attempt will be made to give a complete coverage of the publications on this subject. Because of the confusion in the nomenclature and classification of the various enzymes that oxidize phenols, as to properties and function, it is expedient to confine the survey to the relevant details. [...]

A quarter of a century has elapsed since the first steroid hormone was isolated. Since then, there has been a profound and significant advance in our knowledge of the biogenesis of these steroid hormones and their ultimate fate in the living organism. Less progress, however, has been made in understanding the mode of their physiological action. Studies during the last decade have pointed to a more or less common pathway of steroid biogenesis and metabolism.

There have been remarkable developments in the field of the intermediary metabolism of carbohydrates during the past twenty five years. These developments were due (1) the elucidation of the anaerobic glycolytic breakdown of carbohydrate having its origin in Embden's discovery of phosphoglyceric acid in 1933 and (2) the oxidative tricarboxylic acid cycle discovered by Krebs and Johnson in 1937.The present concepts of the metabolism or carbohydrates centres round these two themes. However, the central role of these pathways is being challenged by the discovery and elucidation of alternative pathways of metabolism.

Ten years ago, the glycolytic system as elucidated by Embden, Meyerhof and others, along with the tricarboxylic acid system as elucidated by Krebs and others, was believed to be the sole pathway of carbohydrate metabolism. Other reactions, known to be concerned with the metabolism of carbohydrates, were considered to be side reactions of the major scheme. [...]

The work of Bourchadat and Sandras (1) was the first recorded attempt to determine the fate of ethanol in the body. They suggested that ethanol is completely burned in the organism to carbon dioxide. Although this observation was confirmed by others, the general belief persisted that ethanol was not oxidised at all, but was eliminated unchanged (2). This theory was based on the results of the animal experiments formed about 1870 which showed that ethanol appeared both in the urine and expired air. Later, Dupre, Anstie and others (3,4,5,6) found that most of the administered ethanol disappears and that the amounts recovered in the urine represent only a very small fraction of the original dose.

The object of this work was the isolation of an estrone conjugate, in a chemically pure form, from human pregnancy urine; and the characterization of this compound by classical procedures. In the course of the investigation, a partial separation of the various estrogen conjugates in pregnancy urine was accomplished through counter current distributions between nor-butanol and alkaline buffers.

In 1868 Miescher (1), by digesting pus cells with pepsin-hydrochloric acid and then shaking with ether, isolated nuclei and prepared from them an unknown compound which he called "nuclein". The substance was acidic in nature, insoluble in dilute acid but readily soluble in dilute alkali, and contained a high proportion of phosphorus. This latter property was noteworthy, for at that time the only known organic compound of phosphorus in the tissues was lecithin. Be subsequently prepared nucleins from a variety of tissues.