Enzyme Function Factors Flashcards

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Questions and Answers

What factors affect enzyme function?

Enzyme concentration, substrate concentration, temperature, pH, salinity, activators, inhibitors, allosteric regulation, metabolic pathways, and efficiency.

How does enzyme concentration affect enzyme function?

As enzyme concentration increases, reaction rate increases, but the substrate can become a limiting factor.

How does substrate concentration affect enzyme function?

As substrate concentration increases, reaction rate increases until all enzymes have their active sites engaged.

How does heat affect enzyme function?

Increased energy level of molecules disrupts bonds in the enzyme and between enzyme and substrate, causing denaturation. Signup and view all the answers

How does the cold affect enzyme function?

It slows down molecular movement, decreasing collisions between enzyme and substrate. Signup and view all the answers

What are endotherms?

Organisms that prefer above-average temperatures, typically warm-blooded animals. Signup and view all the answers

What are ectotherms?

Organisms that prefer below-average temperatures, commonly referred to as cold-blooded animals. Signup and view all the answers

How do changes in pH affect enzyme function?

They add or remove H+, disrupt bonds, and affect the 3D shape of the enzyme. Signup and view all the answers

What pH do most human enzymes prefer?

pH 6-8. Signup and view all the answers

What pH does pepsin prefer?

pH 2-3. Signup and view all the answers

What pH does trypsin prefer?

pH 8. Signup and view all the answers

What is salinity?

Salt concentration. Signup and view all the answers

How do changes in salinity affect enzyme function?

They add or remove cations and anions, disrupting bonds and affecting the enzyme's 3D shape. Signup and view all the answers

Why is the Dead Sea called dead?

Because the enzymes are extremely intolerant of high salinity. Signup and view all the answers

What are activators?

Molecules that help enzymes function, including cofactors, coenzymes, and many vitamins. Signup and view all the answers

What are cofactors?

Non-protein, small, inorganic compounds and ions like Mg, K, Ca, Zn, Fe, and Cu. Signup and view all the answers

What are coenzymes?

Non-protein organic molecules that bind temporarily or permanently to enzymes near the active site. Signup and view all the answers

What are examples of vitamins that act as activators?

NAD (niacin; B3), FAD (riboflavin; B2), Coenzyme A. Signup and view all the answers

What are inhibitors?

Molecules that reduce enzyme activity by keeping the enzyme inactive. Signup and view all the answers

What are competitive inhibitors?

Molecules that compete with the substrate for the active site on the enzyme. Signup and view all the answers

What are some examples of competitive inhibitors?

Penicillin and disulfiram (Antabuse). Signup and view all the answers

What does penicillin do?

Blocks the enzyme bacteria use to build cell walls. Signup and view all the answers

What does disulfiram do?

Treats chronic alcoholism by blocking the enzyme that breaks down alcohol. Signup and view all the answers

How can competitive inhibitors be overcome?

By increasing substrate concentration to outcompete the inhibitor for the active site. Signup and view all the answers

What is a noncompetitive inhibitor?

An inhibitor that binds to a site other than the active site. Signup and view all the answers

What are examples of noncompetitive inhibitors?

Allosteric inhibitors, some anticancer drugs, and cyanide poisoning. Signup and view all the answers

What does an allosteric inhibitor do?

Binds to an allosteric site, causing a conformational change in the enzyme. Signup and view all the answers

What do some anticancer drugs do?

Inhibit enzymes involved in DNA synthesis, stopping division of cancer cells. Signup and view all the answers

What does cyanide poisoning do?

Acts as an irreversible inhibitor of cytochrome C, halting ATP production. Signup and view all the answers

What is irreversible inhibition?

When the inhibitor permanently binds to the enzyme. Signup and view all the answers

What are two types of irreversible inhibitors?

Competitive and allosteric inhibitors. Signup and view all the answers

What does a competitive irreversible inhibitor do?

Permanently binds to the active site. Signup and view all the answers

What does an allosteric irreversible inhibitor do?

Permanently binds to an allosteric site, changing the shape of the enzyme. Signup and view all the answers

What are examples of allosteric irreversible inhibitors?

Nerve gas, sarin, and many insecticides (e.g., malathion, parathion). Signup and view all the answers

What is a cholinesterase inhibitor?

An allosteric inhibitor that doesn't break down the neurotransmitter acetylcholine. Signup and view all the answers

What is feedback inhibition?

Regulation and coordination of production where the final product inhibits an earlier step. Signup and view all the answers

What is allosteric regulation?

Conformational changes in enzymes caused by regulatory molecules. Signup and view all the answers

What are metabolic pathways?

Chemical reactions that are organized in sequences to divide chemical reactions into steps. Signup and view all the answers

How does efficiency relate to factors that affect enzyme function?

Organized groups of enzymes are sequentially arranged, linking endergonic and exergonic reactions. Signup and view all the answers

Study Notes

Factors Affecting Enzyme Function

Key factors include enzyme concentration, substrate concentration, temperature, pH, salinity, activators, inhibitors, allosteric regulation, metabolic pathways, and overall efficiency.

Enzyme Concentration

Increasing enzyme concentration enhances the reaction rate until substrate becomes limiting, leading to saturation where not all enzyme active sites can bind to substrates.

Substrate Concentration

Higher substrate concentration accelerates the reaction rate, but it levels off once all enzymes are saturated, meaning every active site is occupied.

Temperature Effects

Elevated temperature increases molecular energy, which can disrupt weak bonds, potentially causing denaturation and loss of the enzyme's 3D structure.

Cold Temperature Effects

Cold temperatures reduce molecular movement, leading to fewer collisions between enzymes and substrates, thus slowing reaction rates.

Endotherms and Ectotherms

Endotherms are warm-blooded animals that thrive at above-average temperatures; ectotherms are cold-blooded animals that prefer lower temperatures.

pH Influence

Changes in pH introduce or remove hydrogen ions, disrupting bonds and 3D shapes, potentially leading to denaturation of proteins. Most human enzymes prefer a pH of 6-8.
Pepsin, an enzyme in the stomach, functions optimally at a pH of 2-3, while trypsin, found in the small intestine, prefers pH 8.

Salinity

Salinity refers to salt concentration, which affects enzyme function similarly to pH by adding or removing ions, disrupting bonds, and impacting enzyme shape.

Enzyme Activity and the Dead Sea

Extreme salinity in the Dead Sea hinders enzyme functionality, rendering it "dead" in terms of biological activity.

Activators and Cofactors

Activators support enzyme activity and include cofactors (small, inorganic compounds like Mg, K, Ca) and coenzymes (organic molecules like NAD and FAD) that bind near the active site.

Inhibitors

Inhibitors are molecules that reduce enzyme activity, classified into competitive and noncompetitive inhibitors, and play a role in allosteric regulation.

Competitive Inhibition

Competitive inhibitors compete with substrates for the active site. Examples include penicillin, which inhibits bacterial cell wall formation, and disulfiram, which disrupts alcohol breakdown.

Overcoming Competitive Inhibition

Increasing substrate concentration can outcompete competitive inhibitors, thus maintaining enzyme activity.

Noncompetitive Inhibition

Noncompetitive inhibitors bind to an alternative site, altering enzyme shape and function without competing for the active site. Examples include certain anticancer drugs and cyanide.

Irreversible Inhibition

Irreversible inhibitors permanently bind to enzymes, which can occur through competitive or allosteric means, leading to permanent loss of enzyme function.

Allosteric Inhibition

Allosteric inhibitors bind to sites other than the active site, causing conformational changes that render the active site nonfunctional.

Feedback Inhibition

Feedback inhibition is a regulatory mechanism where the end product of a metabolic pathway inhibits an earlier enzyme to prevent overproduction, maintaining efficiency.

Allosteric Regulation

Involves conformational changes in enzymes induced by regulatory molecules. Activators ensure enzymes remain in active forms.

Metabolic Pathways

Chemical reactions of life are organized in pathways to enhance efficiency, allowing control over sequential reactions and preventing unnecessary accumulation of products.

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Description

Explore key factors that influence enzyme function with these informative flashcards. Learn about enzyme concentration, substrate concentration, temperature, and other critical elements that affect the efficiency and regulation of enzymatic reactions.