Cheatography
https://cheatography.com
!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
Enzymes
Enzyme |
Biological molecules (proteins) that act as catalysts and help complex reactions. |
| |
are specific to their substrates and each enzyme has its own optimum pH |
Substrate |
Material upon which an enzyme acts. |
Enzyme inhibition |
important in normal metabolism for control of pathways. |
Reversible inhibitor |
competitive inhibition |
(Raises Km only) Same size and shape with the substrate |
noncompetitive inhibition |
(Lowers Vmax only) inhibitor doesn't mind whether there is a substrate or not. but when the inhibitor binds, it switches off catalysis. |
uncompetitive inhibition |
(Lowers Vmax and Km) the inhibitor can ONLY be on the surface of the enzyme if the substrate is there. |
Irreversible inhibitor |
acts by reacting with the enzyme protein, usually at the active site(substrate site), to permanently block activity. |
Vmax is the maximum rate of an enzyme catalysed reaction i.e. when the enzyme is saturated by the substrate. |
Km is measure of how easily the enzyme can be saturated by the substrate. |
Km and Vmax are constant for a given temperature and pH and are used to characterise enzymes. They can be used to identify types of inhibitors i.e. competitive, non-competitive and uncompetitive. |
|
|
Enzyme in human digestion
|
|
CoFactor
In the case of metal ion cofactors |
Stabilise the structure, not directly involved in the chemistry |
Ca++ with some proteinases |
part of substrate |
Mg++-ATP with some kinases |
part of active site |
Zn++ in alcohol dehydrogenase |
Organic cofactors |
coenzymes |
they do come on and off like other substrates (NAD+) |
prosthetic groups |
a cofactor that forms a permanent part of the enzyme's active site. |
| |
Doesn't come on and off in a catalytic cycle (FAD,PLP) |
NAD+ is both a coenzyme and a substrate
Why use coenzyme in one case and not in the other case? |
Metabolic point: NAD is one of a range of cofactor substances that is present in small concentration |
They turn over and over again to process a large amount of substances |
Pathway is to process large amount with tiny amount of coenzyme |
|
Created By
Metadata
Favourited By
Comments
No comments yet. Add yours below!
Add a Comment
Related Cheat Sheets
More Cheat Sheets by rhettbro