Question

(h) Pseudomonas aeruginosa also uses the Entner-Doudoroff pathway to degrade glucose. Use IMG or BLAST (or MetaCyc) to identify which enzymes in the EMP pathway are missing from P. aeruginosa PAO1.

(i) Biochemical experiments performed by Robertson and McCullough (1968) suggested that Brucella abortus uses the pentose phosphate pathway, instead of the EMP or Entner-Doudoroff pathway, to degrade glucose. The labeling and enzymological results, obtained with B. abortus strain 19 grown in rich media in shaken culture, suggested that key enzymes are missing. Use IMG or BLAST (or MetaCyc) to identify which enzymes in the EMP and ED pathways are missing from B. abortus S19. Is there a discrepancy from experimental results? Explain.

Please only answer if you know the answer. Appreciated

Answer 1

H) in Psudomonas auroginosa , gene for phosphofructokinsase 2 (pfk-2) is absent which is regulatory enzyme.of glycolysis and henve glucose cannot be converted into pyruvate and hence organism cannot utilised glucose as carbon source and caused death.

To overcome this limitation organism operates another pathway called Entner-Doudoroff (ED) pathway to convert glucose into pyruvate.

But this ED pathways produce only one ATP and one NADH and NADPH compared to 2ATP and 2NADH in glycolysis.

I) Brucella abortus strain 19 does not operates or having functional glycolysis, Pentose phosphate pathway or ED pathway and hence cannot utilised glucose as carbon source and can gro only in complex medium.

So key enzyme which are missing from B.abortus stain 19 cold be phospho fructos kinase-2 (pfk-2) so that glycolsis stop, further glucose 6 phosphate dehydrogenase (GPD) is also missing which is regulatory enzyme for Pentose phosphate pathway. And least but not least 2-keto 3-deoxyphospho gluconate aldolase (KDPG) is also absent so that it cannot operate ED pathway.

Hope it's clear..thanks