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1.
J Steroid Biochem Mol Biol ; 52(1): 97-103, 1995 Jan.
Artículo en Inglés | MEDLINE | ID: mdl-7857879

RESUMEN

Lignans and isoflavonoids are two groups of diphenolic phytoestrogens of plant origin which have gained increasing interest because of their possible cancer protective properties. High excretion of these compounds occur in populations at low risk of breast, prostate and colon cancer consuming either high amounts of whole-grain (lignans and some isoflavonoids) or soy products (isoflavonoids and some lignans). We determined the pattern of conjugation of the phytoestrogens in four urine samples from vegetarian or semivegetarian women and in two samples from men. Seven compounds were investigated: enterodiol, enterolactone, matairesinol, diadzein, equol, genistein and O-desmethylangolensin. The fractions quantified are the free fraction, mono- and disulfate, as well as the mono-, di- and sulfoglucuronide fractions. For the fractionation and purification we used ion-exchange chromatography and the determination of the concentrations of each compound in all fractions was done by isotope dilution gas chromatography-mass spectrometry (GLC-MS) using deuterated internal standards of all diphenols. More than 60% of all compounds determined, occurred in the monoglucuronide fraction. Daidzein, enterodiol and equol are excreted to a relatively high extent as sulfoglucuronides and genistein as diglucuronide. We conclude that the general pattern of lignan and isoflavonoid conjugates in urine is similar to that of endogenous estrogens.


Asunto(s)
Estrógenos Conjugados (USP)/orina , Estrógenos no Esteroides , Estrógenos/orina , Isoflavonas/orina , Lignanos/orina , Femenino , Cromatografía de Gases y Espectrometría de Masas , Glucuronatos/orina , Humanos , Masculino , Fitoestrógenos , Preparaciones de Plantas , Caracteres Sexuales , Ésteres del Ácido Sulfúrico/orina
2.
J Bacteriol ; 138(2): 410-7, 1979 May.
Artículo en Inglés | MEDLINE | ID: mdl-571433

RESUMEN

The role of pipecolic acid in the biosynthesis of lysine was investigated in Rhodotorula glutinis, an aerobic red yeast. Supplementation of pipecolic acid in the minimal medium supported the growth of mutants lys2, lys3, and lys5; alpha-aminoadipic acid supported the growth of lys5; but neither alpha-aminoadipic acid nor pipecolic acid supported the growth of mutants MNNG42 and MNNG37. During the growth of the appropriate mutants, pipecolic acid was removed from the growth medium and the intracellular pool. In tracer experiments, radioactivity from [(14)C]pipecolic acid was selectively incorporated into the cellular lysine of lys5 and the wild-type strain. l-Pipecolic acid-dependent enzyme activity did not require any cofactor and was inhibited by mercuric chloride and potassium cyanide. This activity was present in the wild-type strain and all of the mutants tested and was repressed in mutant lys5 when grown in the presence of higher concentration of lysine. The reaction product of pipecolic acid was converted to saccharopine by lys5 enzyme in the presence of glutamate and reduced nicotin-amide adenine dinucleotide phosphate. Mutant MNNG37 lacked the saccharopine dehydrogenase activity, indicating that this step is involved in the conversion of alpha-aminoadipic acid and pipecolic acid to lysine. Mutants MNNG37 and MNNG42 accumulated a p-dimethylaminobenzaldehyde-reacting product in the culture supernatant and in the intracellular pool. Chromatographic properties of the p-dimethylaminobenzaldehyde adduct and that of the pipecolic acid-dependent reaction product were similar. The reaction product and the accumulation product were characterized on the basis of mass and absorption spectra as alpha-aminoadipic-semialdehyde, which in solution remains in equilibrium with Delta(1)-piperideine-6-carboxylic acid. Since alpha-aminoadipic-semialdehyde is a known intermediate of the alpha-aminoadipic acid pathway for the biosynthesis of lysine, it is concluded that pipecolic acid is converted to lysine in R. glutinis via alpha-aminoadipic-semialdehyde and saccharopine.


Asunto(s)
Lisina/biosíntesis , Hongos Mitospóricos/metabolismo , Ácidos Pipecólicos/metabolismo , Rhodotorula/metabolismo , Ácido 2-Aminoadípico/metabolismo , Lisina/análogos & derivados , Mutación , Rhodotorula/genética , Sacaropina Deshidrogenasas/antagonistas & inhibidores , Sacaropina Deshidrogenasas/metabolismo , Especificidad por Sustrato
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