amino acids, proteins and enzymes Flashcards
What are the two key properties of enzymes
High specificity for substrates.
High catalytic rate.
What is an enzyme?
An enzyme is a biological catalyst, typically a protein, that speeds up a chemical reaction without being altered in the process.
What is an enzyme’s active site?
The active site is a small, three-dimensional region of the enzyme where the substrate binds, and the reaction is catalyzed.
How do enzymes reduce activation energy?
Enzymes stabilize the transition state of the substrate, lowering the activation energy required for the reaction to occur.
What is competitive enzyme inhibition?
Competitive inhibition occurs when an inhibitor mimics the substrate’s structure and competes for the active site.
What is non-competitive enzyme inhibition?
Non-competitive inhibition occurs when the inhibitor binds to a site other than the active site, causing a change in the enzyme’s shape and reducing its activity.
What is the role of cofactors in enzyme activity?
What is the role of cofactors in enzyme activity?
How are enzymes classified?
Enzymes are classified into six main categories based on the type of reaction they catalyze: Oxidoreductases, Transferases, Hydrolases, Lyases, Isomerases, and Ligases.
How do enzymes bind to substrates?
Enzymes bind to substrates through the active site, where specific interactions between the enzyme and the substrate occur, leading to catalysis.
How does pH affect enzyme activity?
Changes in pH alter the charge on amino acids in the enzyme, which can affect enzyme structure and function. Each enzyme has an optimal pH for maximum activity.
What is the effect of temperature on enzyme activity?
Increasing temperature generally speeds up enzyme reactions but can eventually denature the enzyme, leading to a loss of activity.
What are the four levels of protein structure?
The four levels of protein structure are:
Primary: Sequence of amino acids.
Secondary: Local folding into α-helices and β-sheets.
Tertiary: 3D folding due to side-chain interactions.
Quaternary: Assembly of multiple polypeptides into a functional protein.
How are amino acids classified based on their R groups?
Amino acids are classified into four groups:
Non-polar, hydrophobic.
Polar, hydrophilic.
Acidic, negatively charged.
Basic, positively charged.
What are essential amino acids?
Essential amino acids are those that cannot be synthesized by the body and must be obtained from the diet.
What drives protein folding?
Protein folding is driven by hydrophobic interactions, hydrogen bonds, electrostatic forces, and covalent bridges.
How are amino acids linked in a protein?
How are amino acids linked in a protein?
Name a disease associated with protein misfolding.
Cystic fibrosis is caused by mutations in the CFTR protein, leading to improper folding and defective chloride ion transport.
What is an example of enzyme regulation through phosphorylation?
Phosphorylation is a common covalent modification that can either activate or inhibit enzyme activity, catalyzed by kinases.
Why are amino acids important in enzyme catalysis?
Amino acids with specific R groups interact with substrates to facilitate chemical reactions, making them essential for enzyme function.
Why is protein conformation important?
The three-dimensional shape of a protein is crucial for its function, as it determines how it interacts with other molecules and carries out its biological role.
