Physiological Studies on Ergot: Further Studies on the Induction of Alkaloid Synthesis by Tryptophan and Its Inhibition by Phosphate
AUTOR(ES)
Robbers, J. E.
RESUMO
The failure of l-leucine to stimulate ergot alkaloid production in a synthetic medium indicates that the previously observed stimulation by tryptophan and tryptophan analogues does not merely represent a nutritional effect. Tryptophan, but not mevalonate or 5-methyltryptophan, is able to overcome the inhibition of alkaloid synthesis by high levels of inorganic phosphate. Therefore, high phosphate levels seem to limit the synthesis of tryptophan; they may, in addition, prevent induction of alkaloid synthesis by preventing accumulation of tryptophan. Experiments which indicate a 2- to 3-fold temporary increase of intracellular free tryptophan and a 20- to 25-fold increase of tryptophan synthetase activity during the transition period between growth and alkaloid production phase are in agreement with the previously postulated induction of alkaloid synthesis by tryptophan. The latter experiments also indicate 4- to 6-fold repression of this enzyme by tryptophan.
ACESSO AO ARTIGO
http://www.pubmedcentral.nih.gov/articlerender.fcgi?artid=251488Documentos Relacionados
- Physiological study of ergot: induction of alkaloid synthesis by tryptophan at the enzymatic level.
- FURTHER STUDIES ON THE ANTIBACTERIAL ACTIVITY OF HUMAN SERUM ON MICROCOCCUS PYOGENES AND ITS INHIBITION BY COAGULASE
- Further studies on the inhibition of pepsin by bile salts.
- Physiological studies of tryptophan transport and tryptophanase operon induction in Escherichia coli.
- Further Studies on Phenylacetylcarbinol Synthesis by Yeast