Enzymes of ammonium assimilation inStreptomyces avermitilis

Novák, Jaromír; Čurdová, E.; Jechová, V.; Cimburková, E.; Ванек, З.

doi:10.1007/bf02814560

Cited by 4 publications

(1 citation statement)

References 14 publications

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“…The general view is that ammonium assimilation proceeds through GDH at high concentrations. GDH : 2-oxoglutaratejNH $ jNAD(P)H glutamatejNAD(P) + However, this enzyme is not present in all Streptomyces species (Brana et al, 1986) and an alternative pathway involving alanine dehydrogenase (ADH) has been proposed in the same high ammonium conditions (Novak et al, 1992). In this case, the synthesis of glutamate would require the function of an alanine transaminase (AT) and would yield the same global reaction.…”

Section: Figmentioning

confidence: 99%

Nitrogen source governs the patterns of growth and pristinamycin production in ‘Streptomyces pristinaespiralis’

Voelker¹,

Altaba²

2001

Microbiology

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Phosphate-limited synthetic culture media were designed to investigate the growth and the pristinamycin production of ' Streptomyces pristinaespiralis ' using different nitrogen sources. During balanced growth, either mineral or organic nitrogen sources were readily utilized. However, glutamate and alanine were used as both nitrogen and carbon source, sparing the utilization of the primary carbon source, glucose. Valine was utilized only for its nitrogen and consequently 2-ketoisovalerate was excreted in the medium. Ammonium prevented the utilization of nitrate. Upon phosphate limitation, glycerol, originating from the breakdown of teichoic acids, was released, allowing the recovery of phosphate from the cell wall and the continuation of growth. Under such conditions, ammonium was excreted following the consumption of glutamate and alanine and was later reassimilated after exhaustion of the primary nitrogen source. The mode of utilization of valine prevented the production of pristinamycins due to excretion of 2-ketoisovalerate, one of their direct precursors. For other nitrogen sources, pristinamycin production was controlled by nitrogen catabolic regulation linked to the residual level of ammonium. In the case of nitrate, the negative regulation was alleviated by the absence of ammonium and production then occurred precociously. In the case of amino acids and ammonium, production was delayed until after exhaustion of amino acids and depletion of ammonium.

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Section: Figmentioning

confidence: 99%