It can only act on a substrate of a specific structure, perform a specific reaction, and generate a product of a specific structure.

For example, urease can only catalyze the hydrolysis of urea to produce CO2 and NH3

The specificity of some enzymes for substrates is not based on the entire substrate molecular structure, but on specific chemical bonds or specific groups in the substrate molecules.

For example: protease

Some enzymes with absolute specificity can distinguish between optical isomers and stereoisomers and can only catalyze a reaction with one optical isomer or stereoisomer.

When the substrate concentration is low: the reaction rate is proportional to the substrate concentration; the reaction is a first-order reaction.

As the substrate concentration increases: the reaction rate no longer accelerates proportionally; the reaction is a mixed-level reaction.

When the substrate concentration reaches a certain level: the reaction rate no longer increases and reaches the maximum rate; the reaction is a zero-order reaction

Ｖ＝Vmax[S]/Km[S]

Km

Not a characteristic constant of an enzyme

Affected by factors such as substrate concentration, buffer type and concentration, and enzyme purity

Not a characteristic constant of an enzyme

Depends on the reaction time

Any substance that can reduce the catalytic activity of an enzyme without causing denaturation of the enzyme protein is called an enzyme inhibitor.

irreversible inhibition

reversible inhibition

Required Activator

optional activator

allosteric adjustment

covalent modification regulation

zymogen activation

induction

repression