Studies on vitamin A

Abstract

The study of the method in the determination of the isoleucine/leucine ratio in-the leucine fraction from the hydrolysates of casein, insulin and edestin gave results which agree with those obtained by microbiological methods except in the case of edestin where there is a very large discrepancy' We are grateful to. Prof. A. C. Chibnall, at whose instigatien this investigation was undertaken, for his interest and helpfil advice. We are indebted to the Medical Research Council (S.E.D.) and to the Agricultural Research Council (G.R.T.) for grants during the tenures of which this investigation was undertaken.

Studies in vitamin A. 9. The role of the thyroid in carotene and vitamin A metabolism

“…In cyclohexane A.... for retinene is 373 mI,. (Ball, Goodwin & Morton, 1948) retineneusing the antimony trichloride test; in order to identify the retinene band at 664 mju. rather than just to measure the absorption at that wave length, the Hilger-Nutting visual spectrophotometer has to be used instead of the Beckman photoelectric instrument; this needed more material than was available.…”

Utilização do TEMPO (N-oxil-2,2,6,6-tetrametilpiperidina) na oxidação de álcoois primários e secundários

“…Muitos reagentes são capazes de realizar estas transformações como, por exemplo, os oxidantes à base de óxidos de cromo (VI) 1 , dióxido de manganês 2 , oxidação de Oppenauer 3 , sais de prata 4 , dentre outros. No entanto, devido ao seu desenvolvimento e complexidade, a química orgânica sintética atual requer reagentes seletivos, capazes de oxidar álcoois em condições reacionais brandas; sendo assim, importantes reagentes foram desenvolvidos, como o reagente de , perrutenato de tetrapropilamônio 6 e reagentes à base de dimetilsulfóxido 7 , sendo a oxidação de Swern 7 a mais conhecida e utilizada.…”

The Fat–soluble Vitamins in Metabolic Processes

“…(2) When the retina is exposed to light, rhodopsin first yields yellow intermediates, which vary in shade according to pH. These transitory products are next transformed to the yellow pigment retinene, which has been identified by Ball, Goodwin & Morton (1948) with vitamin A aldehyde, and the protein opsin.…”