Enzymes: Functions and Applications

Study Notes

Medical Treatment:
- Streptokinase dissolves blood clots.
Genetic Engineering:
- Restriction endonucleases cut DNA at specific sites.
- Ligases join DNA fragments.
Cleaning of Hides:
- Proteases break down proteins in meat and viscera.
Clearing of Juices:
- Pectinase clarifies juice by breaking down pectin.
Alcoholic Drinks:
- Zymase is used in the fermentation process to produce alcohol.
Cheese Formation:
- Rennin, an enzyme from the calf's stomach, is used for cheese production.

Activation Energy: The minimum energy required to initiate a reaction.
Enzymes lower activation energy, speeding up the reaction and facilitating product formation.

Suffix "-ase": Lipase, protease, etc.
Type of Reaction Catalyzed: Dehydrogenase removes hydrogen.
Two-Part System: First part indicates the substrate, and the second identifies the catalyzed reaction (e.g., DNA polymerase: synthesis of DNA).
Source: Papain is derived from papaya.
"IN" Prefix: Pepsin and trypsin were classified before modern nomenclature.

The oxidation of fatty acids (e.g., in metabolism) occurs smoothly and rapidly within the body, despite requiring extreme conditions in a laboratory setting.
In the laboratory, protein breakdown requires boiling for 24 hours in a strong acid solution, yet it occurs quickly in the body under mild conditions.

Lock and Key Model: The enzyme's active site has a specific shape that fits the substrate.
Induced Fit Model: The enzyme's active site changes shape to fit the substrate, facilitating bonding.

Oxido-reductases: Catalyze oxidation-reduction reactions, transferring electrons or protons (H+). Example: Dehydrogenases
Isomerases: Catalyze the conversion of one isomer to another. Example: Glucoisomerases.
Hydrolases: Break down molecules by adding water (hydrolysis). Examples: Esterases, carbohydrases.
Lyases: Break bonds by means other than hydrolysis or oxidation. Example: Histidine decarboxylase.
Ligases (Synthetases): Join two molecules together, using energy from ATP. Example: Pyruvate carboxylase.
Transferases: Transfer a functional group from one molecule to another. Example: Hexokinase transfers a phosphate group from ATP to glucose.

The complete functional enzyme complex, consisting of the apoenzyme and cofactor/coenzyme.

Enzymes with slightly different molecular structures but similar catalytic functions. Example: Lactic dehydrogenase.

The number of substrate molecules acted upon by one enzyme molecule per unit time.

Enzyme Concentration: Increased concentration leads to a faster reaction rate.
Substrate Concentration: Increased concentration increases reaction rate up to a point where enzyme saturation occurs, limiting the rate.
Product Concentration: Accumulation of product can inhibit enzyme activity.
Temperature: Increased temperature generally increases reaction rate, but excessive heat can denature the enzyme.
pH: Each enzyme has an optimal pH range for activity.