Admin: Created page with "* Most enzymes found intracellularly, althougt some are normally found in plasma (e.g., coagulation factors) * Enzymes may appear in serum due to tissue damage or from degraded cells * Enzyme sites: Active site (where substrate interacts) Allosteric site (non-active site, where regularly molecules may bind) * Parts of Enzyme: Holoenzyme: complete, active enzyme Apoenzyme: protein portion of the enzyme, which requires a cofactor for increased activity (or any..."

2025-01-30T17:18:54Z

Created page with "* Most enzymes found intracellularly, althougt some are normally found in plasma (e.g., coagulation factors) * Enzymes may appear in serum due to tissue damage or from degraded cells * Enzyme sites: ** Active site (where substrate interacts) ** Allosteric site (non-active site, where regularly molecules may bind) * Parts of Enzyme: ** Holoenzyme: complete, active enzyme ** Apoenzyme: protein portion of the enzyme, which requires a cofactor for increased activity (or any..."

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* Most enzymes found intracellularly, althougt some are normally found in plasma (e.g., coagulation factors)
* Enzymes may appear in serum due to tissue damage or from degraded cells
* Enzyme sites:
** Active site (where substrate interacts)
** Allosteric site (non-active site, where regularly molecules may bind)
* Parts of Enzyme:
** Holoenzyme: complete, active enzyme
** Apoenzyme: protein portion of the enzyme, which requires a cofactor for increased activity (or any activity at all)
** Co-factor: non-portion portion that transiently binds to the enzyme to enhance the apoenzyme's ability to catalyze a reaction
*** Co-enzymes: organic co-factors that are loosely bound to act as intermediate carriers of electrons, etc.
**** Vitamin B
**** NAD, NADP, NADH
*** Prosthetic groups: organic co-factors that are permanently bound to apoenzyme and undergo chemical changes during the reaction
**** Heme
*** Metal ions: inorganic ions that activate enzymatic reactions
**** Zn2+, Mg2+, Fe2+, occasionally anions like Cl

Factors Affecting Enzymes

* pH (optimal pH for maximal activity)
* temperature (increased temperature increases enzyme activity until it is denatured)
* co-factors
* inhibitors

Proenzymes (Zymogens)

* Inactive enzyme or precursor that is activated by an activator
** Digestive enzymes inactive to protect tissue when not required

Isoenzymes

* Functionally identical (same active centre), but the enzyme itself is different physically (e.g., different amino acid side chains)
* Identified by different chemical properties
* Creatine kinase
* Lactate dehydrogenase

Enzyme Specificity

* Absolute (substrate specificity)
* Bond specificity
* Group specificity
* Stereoisomeric specificity

Reaction Kinetics

* 1st Order Reaction
** Reaction rate increases in proportion to the amount of substrate added
* Zero Order Reaction
**

Enzymes - Revision history