Consider the following hypothetical metabolic pathway:(a) Under intracellular conditions,...

Consider the following hypothetical metabolic pathway:

(a) Under intracellular conditions, the activity of enzyme X is 100 pmol/l06 cells/sec. Calculate the effect on metabolic flux rate (pmol/106 cells/sec) of B → C of the following treatments. Calculate as % change (increase or decrease).

Treatment % Change in flux

Inhibitor that reduces activity of X by 10% Activator that increases activity of X by 10%

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 (b) Now consider a substrate cycle operating with enzymes X and Y in the same hypothetical metabolic pathway:

Under intracellular conditions, the activity of enzyme X is 100 pmol/106 cells/sec, and that of enzyme Y is 80 pmol/106 cells/ sec. What are the direction and rate (pmol/106 cells/sec) of metabolic flux between B and C?

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 (c) Calculate the effect on direction and metabolic flux rate of the following treatments. Calculate as % change (increase or decrease).

Treatment	Direction of flux (B → C or C → B)	% Change in flux
Inhibitor that reduces activity of X by 10%
Activator that increases activity of X by 10%
Doubling the activity of enzyme Y

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 (d) Briefly summarize the regulatory advantage(s) of a substrate cycle in a pathway.