Enzymes: Introduction, Kinetics, and Inhibition

Practice flashcards covering enzyme basics, classification, kinetics (Michaelis-Menten), and types of inhibition.

Bio-washing of denim involves the use of the enzyme __________ to create a faded effect.

cellulase

The most widely used source of the cellulase enzyme used in industrial denim washing is __________.

fungal

Cellulases break the __________ bonds found in cellulose fibers to release indigo dye.

glycosidic

Enzymes are __________ catalysts that speed up chemical reactions in living organisms without being used up.

biological

Enzymes lower the __________ energy of a reaction to speed up the biochemical process.

activation

The suffix __________ is usually added to the name of a substrate or reaction type to name an enzyme.

-ase

In the Enzyme Commission (EC) system, the group __________ catalyzes oxidation-reduction reactions.

Oxidase / Dehydrogenase or Reductase

Enzymes that use water to break chemical bonds are classified as __________.

Hydrolase

The enzyme class __________ catalyzes reactions where new bonds are formed between carbon and another atom, requiring energy.

Ligase

The __________ structure of an enzyme refers to the three-dimensional interactions between various $\alpha$-helices and $\beta$-sheets.

Tertiary

In the __________ hypothesis, the substrate and the active site of the enzyme both change shape slightly during the binding process.

induced fit

The __________ of an enzyme is the region formed by protein folding where the substrate binds.

active site

A __________ curve is used to calculate the initial velocity ($V_o$) of a reaction by measuring product formation over time.

Progress

The __________ curve shows the relationship between the rate of reaction and substrate concentration.

Michaelis-Menten

$V_{max}$ represents the __________ velocity of an enzyme-catalyzed reaction, achieved at infinitely high substrate concentrations.

maximum

The parameter __________ is the substrate concentration at which $\frac{1}{2} V_{max}$ is achieved.

$$K_m$$

A low value of $K_m$ indicates a __________ affinity between the enzyme and the substrate.

high

__________ enzyme inhibitors bind tightly to the enzyme, often forming covalent bonds, to create a permanent complex.

Irreversible

Aspirin works by inhibiting the pain-enhancing enzyme __________ by acetylating a serine residue in its active site.

COX2

In __________ inhibition, the inhibitor and substrate compete for the same active site on the enzyme.

competitive

Competitive inhibitors cause the value of __________ to increase, while the value of $V_{max}$ remains unchanged.

$$K_m$$

Non-competitive inhibitors lower the __________ value without changing the $K_m$ value.

$$V_{max}$$

__________ inhibition occurs when the end product of a pathway binds to an allosteric site on an enzyme to shut down its own production.

Feedback

Pancreatic lipase inhibitors are investigated as diet pills because they bind irreversibly to the enzyme's active site, preventing the hydrolysis of __________.

triglycerides