Enzymology

48 topics with brief breakdowns: definitions, key facts, and classroom questions.

Enzymology is the foundation of biochemistry. In this section, we examine how biological catalysts work: from active site structure and the role of coenzymes (NAD, FAD, biotin) to complex kinetics and the Michaelis constant. You will study enzyme classification, temperature effects, and regulatory mechanisms, including allosteric control, phosphorylation, and activation by partial proteolysis.

In seminars and exams, clinical application is subject to the strictest scrutiny. Pay special attention to enzymodiagnostics (markers of myocardial infarction – LDH isoenzymes and creatine kinase), as well as mechanisms of enzyme inhibition. Understanding how succinate dehydrogenase with malonate, acetylcholinesterase, or sulfonamides work will lay a solid foundation for pharmacology. Knowledge of enzymopathies and enzyme therapy is mandatory for transitioning to clinical departments.

Section Topics

General characteristics and properties of enzymesEnzymes are biological catalysts of protein nature Active site of enzymesThe active site of enzymes is a strictly defined specialized Enzyme specificityEnzyme specificity is a key property of biological Mechanism of enzymatic catalysisEnzymatic catalysis is a fundamental biochemical process pr Cofactors and coenzymesMost enzymes require for the manifestation of catalytic activity Nicotinamide coenzymesNicotinamide coenzymes are crucial components of enzymes ensuring Flavin coenzymesFlavin coenzymes are essential non-protein components of enzymes Pyridoxal phosphatePyridoxal phosphate is a key coenzyme responsible for proper LipoamideLipoamide is an essential coenzyme structure, with the biochemical precursor Ascorbic acidAcidum ascorbicum BiotinBiotin is an essential biologically active substance acting as Water-soluble vitaminsWater-soluble vitamins are a group of organic compounds that Classification and nomenclature of enzymesIn medical biochemistry, all biological catalysts are strictly systematized OxidoreductasesOxidoreductases are a vital class of enzymes catalyzing oxidation TransferasesTransferases are a broad class of enzymes catalyzing reactions between HydrolasesHydrolases are a broad class of enzymes whose main task is LyasesLyases are enzymes that catalyze the non-hydrolytic cleavage Measurement of enzyme activityThe catalytic capacity of any enzyme is assessed through the rate Enzyme kineticsEnzyme kinetics studies the dependence of the catalytic rate Michaelis constantThe Michaelis constant ($K_m$) is a baseline kinetic characteristic Competitive enzyme inhibitionCompetitive inhibition is a type of reversible decrease in the rate of enzyme Irreversible enzyme inhibitionIrreversible inhibition is a process in which the inhibitor forms Succinate dehydrogenase and malonateThe interaction of the enzyme succinate dehydrogenase with malonic acid (ma AcetylcholinesteraseAcetylcholinesterase (AChE) is an enzyme whose main function consists Regulation of enzyme activityThe function of biocatalysts in a living cell is a strictly ordered process Allosteric regulation of enzymesAllosteric regulation of enzymes is the process of altering their catalytic Phosphorylation and dephosphorylation of enzymesPhosphorylation and dephosphorylation is a mechanism for rapid tuning EnzymodiagnosticsEnzymodiagnostics is a method for recognizing diseases and pathological IsoenzymesIsoenzymes are a group of enzymes that catalyze the same Lactate dehydrogenaseLactate dehydrogenase (LDH) is a key carbohydrate metabolism enzyme which Creatine kinaseCreatine kinase (CK) is an enzyme catalyzing the reaction of formation of m EnzymopathiesPrimary enzymopathies are a broad group of hereditary diseases Enzyme therapyEnzyme therapy is a field in medicine based on the use of Mechanism of action of sulfonamidesSulfonamides are a group of antibacterial bacteriostatic agents MAO inhibitorsMAO inhibitors are used for the drug treatment of depression. Their Mechanism of action of atropineAtropinum Mechanism of action of caffeineCoffeinum Enzymodiagnostics of myocardial infarctionEnzymodiagnostics of myocardial infarction is a laboratory method for confirming Purine nucleotide synthesisPurine nucleotide synthesis is a multistep metabolic pathway Main coenzymesCoenzymes are vital organic molecules that bind Determination of lactate dehydrogenase (LDH) activityLactate dehydrogenase (LDH) is a crucial enzyme that catalyzes Effect of temperature on enzyme activityTemperature is one of the main factors determining the rate of enzyme Covalent modification of enzymesCovalent chemical modification is one of the fastest and most widespread Enzyme inhibitionInhibition of enzyme activity is the process of specific reduction Non-competitive and irreversible inhibitionEnzyme inhibition is the process of reducing their catalytic Activation of enzymes by partial proteolysisPartial (limited) proteolysis is a regulatory mechanism in which Enzymes in medicine and enzymopathiesEnzyme therapy is the use of specific enzymes as Structure of enzymesEnzymes are biological catalysts of protein nature responsible for

Frequently asked questions for this section

Does the energy of a chemical system change in the presence of an enzyme?

No, enzymes keep the total energy of the chemical system constant; they merely lower the activation energy, accelerating the attainment of equilibrium.

What is the active center of an enzyme?

It is a specific region of the protein molecule capable of binding complementarily to the substrate and ensuring its chemical catalytic transformation.

What determines the specificity of action of any enzyme?

Enzyme specificity is entirely determined by the structure of its active site, which is complementary to specific molecules.

Does the enzyme change the overall thermodynamics of the reaction?

No, the enzyme does not alter the reaction thermodynamics. The initial and final energy levels (and the ΔG value) remain unchanged. The enzyme affects only the kinetics, accelerating the process.

What is the difference between a cofactor and a coenzyme?

A cofactor is a broad term encompassing any non-protein substances required by an enzyme (metal ions and organic molecules). A coenzyme is a specific type of cofactor that is specifically an organic substance (often a vitamin derivative).

Which vitamin is the precursor for NAD+ and NADP+?

Their precursor is vitamin PP (niacin, vitamin B3), in the form of nicotinic acid or nicotinamide.

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