Different molecular forms of an enzyme that catalyse the same reaction but vary in kinetic properties or tissue location.
Isoenzymes (isozymes) arise from different genes or splicing and differ in kinetics or regulation. Lactate dehydrogenase has heart (H4) and muscle (M4) forms suited for aerobic or anaerobic work.
Their distribution in blood is used in diagnosis.
Different molecular forms of an enzyme that catalyse the same reaction but vary in kinetic properties or tissue location.
Isoenzymes is one of the 51 topics in Biomolecules & Biochemistry. It is rated Advanced, so it suits learners who want specialist depth. Related topics in this area include Allosteric Regulation, Michaelis-Menten Kinetics, Active Site.
Raised cardiac troponin and CK-MB are markers of a heart attack.
Work through the Beginner topics in Biomolecules & Biochemistry first, such as Water Properties, Carbon Chemistry, Carbohydrates, then return to Isoenzymes. Advanced topics assume the Intermediate vocabulary.
The closest topics to Isoenzymes are Allosteric Regulation, Michaelis-Menten Kinetics, Active Site, Carbon Chemistry. Comparing them side by side is a good way to see how the ideas connect.
Read the summary and the in-depth section, then use the quick check on the interactive lesson for Isoenzymes. To practise the whole of Biomolecules & Biochemistry, use the Biomolecules & Biochemistry quiz.
Isoenzymes: Different molecular forms of an enzyme that catalyse the same reaction but vary in kinetic properties or tissue location. Allosteric Regulation: Binding of a molecule at a site other than the active site changes enzyme shape and activity. Read both side by side and note what each one explains.
First, read the summary and write the definition in your own words. Second, read the in-depth section and note any example. Third, compare it with Allosteric Regulation and explain the difference aloud. Finally, take the Biomolecules & Biochemistry quiz and come back to this page for any question you miss.
Binding of a molecule at a site other than the active site changes enzyme shape and activity.
⚗️ Biomolecules & BiochemistryModels reaction velocity as Vmax times substrate over Km plus substrate, describing enzyme saturation.
⚗️ Biomolecules & BiochemistryThe specific pocket on an enzyme where the substrate binds and the reaction takes place.
⚗️ Biomolecules & BiochemistryCarbon forms four covalent bonds, allowing chains, rings and the huge variety of organic molecules in living things.
⚗️ Biomolecules & Biochemistry