RATE LIMITATION WITHIN A SINGLE ENZYME IS DIRECTLY RELATED TO ENZYME
INTERMEDIATE LEVELS
Boris N. Kholodenko, Hans V. Westerhoff and Guy C. Brown
(1994) FEBS Lett., in the press.
INFO: HW at NKi.NL
SUMMARY:
The extents to which different rate constants limit the steady state rate of an
isolated enzyme can be quantified as the control coefficients of those
constants and elemental steps. We have found that the sum of the control
coefficients of rate constants characterizing unidirectional rates depleting a
particular enzyme intermediate is equal to the concetration of that eny,me
intermediate as a fraction of the total enzyme concentration. Together with
simple measurements this powerful relation may be used (a) to estimate certain
enzyme intermediate levels, in particular the free enzyme concentration, and
(b) to estimate the control coefficients of rate constants and steps.
Key words: Rate limitation, metabolic control analysis, control coefficients,
enzyme kinetics
