SUBSTRATE (BIOCHEMISTRY)

In biochemistry, a 'substrate' is a molecule upon which an enzyme acts. Enzymes catalyze chemical reactions involving the substrate(s). The substrate binds with the enzyme's active site, and an enzyme-substrate complex is formed. The substrate is broken down into a product and is released from the active site. The active site is now free to accept another substrate molecule. An example of a substrate would be milk and the enzyme added would be rennin which causes milk to set. Another example would be the reaction of catalase in the decomposition of hydrogen peroxide.
:2 H₂O₂ → 2 H₂O + O₂.
A general equation is as follows:
E + S ⇌ ES → EP ⇌ E + P
'where E = enzyme, S = substrate(s), P = product(s)'
Note that only the middle step is irreversible.
By increasing the substrate concentration, the rate of reaction will increase due to the increase in likelihood of enzyme-substrate complexes forming, this occurs until the enzyme becomes the limiting factor.

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See also

See also

★ Enzyme kinetics

★ Enzyme assay
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