Enzyme activity - (Mar/17/2008 )

Are Vmax and the specific activity of one enzyme same things!

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Enzyme activity is moles substrate converted/ unit time (mols/sec). Units: katals.

Specific activity is enzyme activity expresses per unit mass of total protein present. Units: kat /mg

Vmax is the max reaction velocity (at infinite substrate concentration). It is a function of the amount of the enzyme and is the appropriate rate to use when determining the specific activity of a purified enzyme.

Hope that helps

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But the unit of specific activity and the Vmax are the same. Or not!

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yes but specific activity is a value measured at certain conditions; Vmax is determined at ideal conditions in vitro (which might be never met in a cell)

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Thus, can Vmax be equivalent with specific activity?

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yes, under ideal conditions

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OK! Thanks a lot.

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