Biomidterm II - Nov 11th Flashcards

Question

When the partial pressure of oxygen in venous blood is 30 torr, the YO2 value for myoglobin is ______ given that the k value is 2.8 torr. a) 0.55 b) 0.91 c) 2.8 torr d) 0.95 e) none of the above

Answer 1

❑Mainly act as energy resource ❑Protection as structural materials ❑Intercellular communication ❑Stabilization of protein structures

Answer 2

Haworth projections are a two-dimensional representation of cyclic monosaccharides that effectively convey stereochemical information. - Cyclic Structure: They depict sugars in their cyclic forms (pyranose or furanose) as flat rings, with each vertex representing a carbon atom. - Anomeric Carbon: The anomeric carbon is clearly marked, with the orientation of the hydroxyl group indicating whether it is in the α (downward) or β (upward) configuration. - Substituent Orientation: Other substituent groups are shown with their positions indicating stereochemistry, and hydrogen atoms are often omitted for simplicity.

Answer 3

The two anomeric forms of cyclic sugars are alpha (α) and beta (β), distinguished by the orientation of the hydroxyl group (-OH) on the anomeric carbon: - Alpha (α) Anomer: The -OH group on the anomeric carbon is positioned downward (trans to the CH₂OH group) in the Haworth projection. For example, α-D-glucose features this configuration. - Beta (β) Anomer: The -OH group is positioned upward (cis to the CH₂OH group), as seen in β-D-glucose. - These forms can interconvert in solution through _mutarotation,_ where the cyclic structure temporarily opens to allow the hydroxyl group to change orientation, impacting the sugar's properties and biological functions.

Answer 4

- N-Acetylneuraminic acid (Neu5Ac) is a nine-carbon sugar, also known as sialic acid, that plays a vital role in the modification of glycoconjugates like glycoproteins and glycolipids. - Structure and Composition: It contains an N-acetyl group and is characterized by its cyclic form, which includes a carboxyl group, a hydroxyl group, and an acetamido group. - Biological Significance: Neu5Ac is crucial for cell-cell recognition, immune response modulation, and neurological functions, often found at the terminal positions of glycan chains, enhancing cell adhesion and preventing immune detection. - Complex Sugar Modification: Through the process of sialylation, Neu5Ac modifies glycoproteins and glycolipids, impacting their stability, biological activity, and overall functionality, contributing to a diverse range of glycan structures with specific biological roles

Answer 5

Found in: - Nucleotides: In DNA and RNA, an N-glycosidic bond connects the nitrogenous base (adenine, thymine, cytosine, guanine, or uracil) to the 1' carbon of the sugar (ribose in RNA or deoxyribose in DNA). - Glycoproteins: N-glycosidic bonds link sugars to the amino group of asparagine residues in glycoproteins, forming N-linked glycosylation.

Answer 6

Glycoconjugates are molecules that consist of carbohydrates covalently bonded to other types of biomolecules, such as proteins or lipids. This combination allows glycoconjugates to play essential roles in cell recognition, signalling, and structural integrity. Key types and roles include: Proteoglycans: These are heavily glycosylated proteins, containing large carbohydrate (glycosaminoglycan) chains. Proteoglycans are abundant in connective tissue, providing structural support and participating in cellular signalling pathways

Answer 7

N-Acetylglucosamine (NAG): This amino sugar has a six-carbon structure with an acetyl group at the amino position. It forms part of the repeating disaccharide units in peptidoglycan, linking to NAM through β-1,4-glycosidic bonds. N-Acetylmuramic Acid (NAM): Similar to NAG but contains a lactic acid side chain at the C3 position, NAM also alternates with NAG in the peptidoglycan structure. Its unique side chain allows for peptide cross-linking, enhancing the rigidity and strength of the bacterial cell wall.

Answer 8

Structure and Function: Pentaglycine provides flexibility and connectivity in the peptidoglycan layer, contributing to its structural integrity and rigidity. Linkage with Lysine and D-Alanine: Pentaglycine links the side chain of a lysine (Lys) residue from one tetrapeptide to the D-alanine (D-Ala) of a neighboring tetrapeptide, forming covalent cross-links. Cross-Linking Importance: This interaction enhances the strength and resistance of the peptidoglycan structure, which is essential for bacterial survival against osmotic pressure.

Answer 9

Penicillin is a beta-lactam antibiotic that inhibits bacterial cell wall synthesis by targeting penicillin-binding proteins (PBPs), which are essential for cross-linking peptidoglycan layers. Beta-Lactamase Resistance: Some bacteria produce beta-lactamase enzymes that hydrolyze the beta-lactam ring in penicillin, rendering it ineffective. Combination Therapy: To combat this resistance, penicillin is often combined with beta-lactamase inhibitors, such as clavulanic acid, which protect penicillin from degradation, enhancing its effectiveness against resistant bacteria. This combination therapy improves the treatment of infections caused by beta-lactamase-producing bacteria, maintaining the utility of penicillin in clinical settings.

Answer 10

1. O-linked glycoproteins: carbohydrate is linked to the protein through OH group the side chain of serine, threonine or tyrosine 2. N-linked glycoproteins: carbohydrate is linked to the protein through the side chain of Asparagine (N)

Answer 11

Glycoprotein biosynthesis in eukaryotic cells involves several key steps: 1. Protein Synthesis: The process begins with the transcription of the gene encoding the glycoprotein into mRNA, followed by translation into a polypeptide chain in the cytoplasm. A signal peptide directs the nascent protein to the endoplasmic reticulum (ER). 2. Glycosylation: In the ER, the polypeptide undergoes co-translational translocation and folding, followed by N-glycosylation, where an oligosaccharide is attached to asparagine residues. O-glycosylation occurs in the Golgi apparatus, adding sugars to serine or threonine residues. 3. Golgi Modifications and Transport: The glycoprotein is transported to the Golgi apparatus, where it undergoes further modifications and sorting for its final destination, such as the plasma membrane or secretion outside the cell.

Answer 12

O-linked carbohydrates can include any single or short carbohydrate group linked via oxygen. O-linked oligosaccharides specifically refer to more complex, branched sugar chains attached through oxygen, often with intricate biological roles.

Answer 13

- The 18 = total number of carbons in the acid - The 3 = number of double bonds - The second 3 = position of last double bond from terminal methyl group

Answer 14

Hydrogenation Process: Hydrogenation is the chemical process of adding hydrogen to unsaturated fats, often converting oils into a more solid form. This process is typically achieved by exposing the fat to hydrogen gas at high temperatures in the presence of a metal catalyst (usually nickel). Formation of Trans Fats: Partial hydrogenation can cause some of the natural cis configurations of double bonds in unsaturated fats to flip into trans configurations. This creates trans fats, which have a straighter molecular shape, allowing them to solidify at room temperature.

Answer 15

Structure: Triacylglycerols (also called triglycerides) are lipid molecules consisting of three fatty acid chains attached to a glycerol backbone. Each fatty acid is linked to glycerol through an ester bond, forming a stable structure. Function: Triacylglycerols serve as the body's primary form of long-term energy storage. They are stored in adipose tissue and can be broken down during fasting or energy-demanding activities to release fatty acids and glycerol for fuel. Properties: Triacylglycerols can be solid (fats) or liquid (oils) at room temperature, depending on the types of fatty acids they contain. Saturated fats are more likely to be solid, while unsaturated fats are usually liquid.

Answer 16

Structure: Glycerophospholipids are composed of a glycerol backbone, two fatty acid chains, and a phosphate group that is often further modified with additional polar head groups (such as choline, ethanolamine, or serine). This amphipathic structure allows them to form bilayers in aqueous environments. Function: They are essential components of cell membranes, contributing to membrane fluidity and integrity. The hydrophobic tails face inward, while the hydrophilic head groups face outward, creating a barrier that separates the internal and external environments of the cell.

Answer 17

Cell Membrane Structure and Fluidity: Sphingolipids, including gangliosides and ceramides, are essential for maintaining cell membrane integrity and fluidity. Their unique structures contribute to the formation of lipid rafts, which support various membrane proteins and signalling pathways, particularly in neurons. Cell-Cell Recognition and Communication: Gangliosides play a crucial role in cell-cell interactions, mediating immune responses and neuronal communication. They serve as recognition molecules that influence how cells respond to pathogens and communicate during tissue development and repair. Regulation of Cellular Processes: Ceramides are important for regulating processes such as apoptosis and inflammation. They act as signalling molecules that can trigger programmed cell death, crucial for tissue homeostasis, and are involved in inflammatory responses linked to diseases like obesity and neurodegeneration

Answer 18

Structure: Sphingolipids are composed of a sphingosine backbone, a long-chain fatty acid, and a polar head group. Unlike glycerol-based lipids, sphingolipids contain a single fatty acid linked to the sphingosine through an amide bond, which gives them unique properties. Function: They play critical roles in cellular signalling and recognition. Sphingolipids are essential components of cell membranes, particularly in the nervous system, where they contribute to the formation of myelin sheaths that insulate nerve fibres. Types: Key subclasses of sphingolipids include ceramides, sphingomyelins (which contain a phosphocholine head group), and glycosphingolipids (which have sugar residues).

Answer 19

Chemical Structure: Vitamin D2 (ergocalciferol) and D3 (cholecalciferol) are sterol derivatives derived from cholesterol. D2 is produced by UV irradiation of ergosterol, while D3 is synthesised in the skin upon UVB exposure. Biological Functions: Both vitamins are essential for calcium and phosphorus metabolism, promoting bone health by enhancing the absorption of these minerals in the intestine. They regulate parathyroid hormone levels, support bone mineralisation, and help maintain bone density. Additionally, Vitamin D plays a role in immune function, influencing the activity of immune cells and reducing inflammation, which may have implications for chronic disease prevention and overall health

Answer 20

Amphipathic Nature: Glycerophospholipids and sphingolipids have an amphipathic structure, with hydrophobic tails and hydrophilic head groups. This allows them to form stable bilayers in aqueous environments, creating a barrier that separates the cell's interior from the outside. Membrane Fluidity: These lipids enhance the fluidity and flexibility of cell membranes. Glycerophospholipids can vary in fatty acid composition, while sphingolipids help organise membrane proteins, which is essential for proper cellular function. Cell Signalling: Both types of lipids are involved in cell signalling and recognition. Glycerophospholipids participate in signalling pathways, and sphingolipids, such as gangliosides, facilitate cell-cell communication, impacting processes like growth and immune responses.

Answer 21

Composition Differences: The inner and outer leaflets of the plasma membrane differ in their lipid and protein compositions. The outer leaflet predominantly contains sphingolipids and phosphatidylcholine, which contribute to a positive charge on the extracellular side. In contrast, the inner leaflet is rich in phosphatidylethanolamine, phosphatidylserine, and phosphatidylinositol, which play key roles in intracellular signalling and membrane dynamics. Functional Roles: The distinct compositions of the leaflets contribute to their specific functions. The outer leaflet is involved in cell recognition, signalling, and interactions with the extracellular environment, while the inner leaflet is crucial for anchoring cytoskeletal proteins and facilitating intracellular communication. Asymmetry Importance: The asymmetry between the inner and outer leaflets is vital for maintaining membrane integrity and functionality. This asymmetry affects membrane fluidity, stability, and the ability to respond to external signals, ensuring proper cellular processes such as apoptosis and vesicle trafficking

Answer 22

= Glycans are complex carbohydrates composed of sugar molecules that are linked together to form larger structures, such as oligosaccharides and polysaccharides. They play crucial roles in biological processes, including cell recognition, signalling, and the formation of structural components in cells and tissues.

Answer 23

Dynamic Interaction: Lipid-anchored membrane proteins are covalently bonded to lipids in the bilayer, allowing them to move laterally and interact with other membrane components, influencing cellular signalling pathways. Regulatory Mechanisms: These proteins can act as switching devices by undergoing conformational changes or releasing from the membrane in response to specific signals, enabling regulation of cellular processes like signal transduction and adhesion. Functional Versatility: Their ability to integrate and detach from the membrane allows lipid-anchored proteins to modulate receptor activity, facilitate enzyme interactions, and act as scaffolds for protein complexes, enhancing cellular responsiveness.

Answer 24

Myristoylated proteins are proteins that have a myristoyl group (a 14-carbon saturated fatty acid) covalently attached to their N-terminal glycine residue, which helps anchor them to cell membranes. This lipid modification facilitates membrane association, influencing protein localization, stability, and interactions in various cellular processes, including signal transduction.

Answer 25

are channel-forming proteins in the outer membrane of gram-negative bacteria or the outer membrane of mitochondria

Answer 26

fluid mosaic model The fluid mosaic model describes the cell membrane as a flexible lipid bilayer with proteins embedded or attached, allowing them to move like icebergs in a sea of lipids. It suggests that membranes are dynamic and semi-permeable, with lipids such as phospholipids and cholesterol providing fluidity and stability. This structure allows the membrane to adapt to environmental changes and facilitates processes like communication and molecule transport. It also explains functions like endocytosis and exocytosis, crucial for cellular activity.

Answer 27

Hemoglobin low high affects cooperative

Answer 28

Myoglobin does not affect independent

Answer 29

- Proved by Hill equation: Overall, at lower O2 concentrations, low O2 binding affinity, at higher O2 concentrations, higher O2 binding affinity. - When oxygen concentration is low (e.g., in tissues needing oxygen), haemoglobin releases O₂ to supply the tissue, rather than binding it tightly. At high O₂ concentrations (like in the lungs), haemoglobin binds O₂ more readily to transport it to tissues. The cooperative binding of haemoglobin enhances this transport efficiency, ensuring oxygen is released where it is needed most.

Answer 30

prosthetic group

Answer 31

- Translocon embedding of TM proteins happens in four steps: 1. Signal peptide on end of chain attaches to wall of translocon 2. Protein (peptide chain) is fed through translocon until the hydrophobic stop transfer signal halts production 3. Signal peptidase cleaves the signal sequence 4. Peptide sequence moves laterally through the translocon and embeds itself into the membrane

Answer 32

- F-Type = ATP synthase (pump proton, make ATP) - V-Type = Pump proton into lysosomes, endosome, (for degredation reasons?) use ATP - A-Type = found in archaea and work like F-types but pump anions instead of protons - ABD = Legit just pinball arms that throw molecules from one side to another

Answer 33

In the Na⁺/K⁺ ATPase cycle, E2-P * 2K⁺ represents a specific conformational state of the enzyme. Here’s what it means: E2: The enzyme is in a conformation that favours the binding and release of potassium (K⁺) ions on the extracellular side of the membrane. P: Indicates phosphorylation of the enzyme, providing energy for ion transport. * 2K⁺: Two potassium ions are bound to the enzyme in this state, ready to be transported into the cell. This step is part of the mechanism allowing the Na⁺/K⁺ pump to maintain ion gradients across the cell membrane.

Answer 34

Chymotrypsin is a digestive enzyme that plays a crucial role in the breakdown of proteins in the small intestine. It is a type of serine protease, meaning it cleaves peptide bonds in proteins using a serine residue in its active site. Chymotrypsin specifically targets peptide bonds adjacent to large, aromatic amino acids such as phenylalanine, tryptophan, and tyrosine. By breaking these peptide bonds, it helps to degrade proteins into smaller peptides, which are then further broken down into amino acids by other enzymes. This process is essential for protein digestion and the absorption of amino acids, which are used for various physiological functions, including tissue repair and enzyme synthesis.

Answer 35

**Acid-Base Catalysis:** Enzymes can facilitate reactions by donating or accepting protons (H⁺). Acidic or basic residues in the enzyme’s active site can act as proton donors or acceptors, stabilising transition states or intermediates and speeding up the reaction. **Covalent Catalysis:** In this mechanism, the enzyme forms a transient covalent bond with the substrate during the reaction. This intermediate can then be more easily converted to the product. The enzyme often acts as a nucleophile, attacking electrophilic centres of the substrate. **Metal Ion Catalysis:** Many enzymes use metal ions to assist in the catalytic process. Metal ions can stabilise negative charges, facilitate electron transfers, or help in substrate binding. Transition metals like Zn²⁺, Fe²⁺, and Mg²⁺ are commonly involved in these reactions. **Proximity and Orientation Effects:** Enzymes bring substrates into close proximity and orient them in an optimal position for the reaction to occur. This reduces the entropic barrier to the reaction and increases the probability of effective collisions between the reacting molecules. **Preferential Binding of Transition State Complex:** Enzymes bind to the transition state of the reaction more strongly than to the substrate or product. This preferential binding stabilises the transition state, lowers the activation energy, and accelerates the reaction

Answer 36

Acid-base catalysis: In this mechanism, the enzyme helps the reaction by donating or accepting protons (H⁺). Acid-base catalysis can either speed up the reaction by donating a proton to stabilize a negatively charged transition state or by accepting a proton to stabilize a positively charged transition state.

Answer 37

A series of acid catalysis and/or base catalysis may occur in one catalytic reaction (concerted) Many amino acid side chains can participate in acid-base catalysis: Asp, Glu, His, Cys, Tyr, Lys

Answer 38

- RNase A is an enzyme that acts as an acid-base catalyst in the cleavage of RNA molecules. It catalyzes the hydrolysis of the phosphodiester bond in RNA through a two-step mechanism, where His12 and His119 act as key acid-base catalysts. These histidine residues alternately donate and accept protons to facilitate the reaction, helping to stabilize the transition state. - As for the number of S-S bonds in RNase A, there are two disulfide bonds (S-S) in its structure. These bonds help maintain the enzyme's stable three-dimensional conformation, which is essential for its catalytic activity.

Answer 39

Covalent catalysis: This involves the formation of a temporary covalent bond between the enzyme and the substrate. **The enzyme acts as a nucleophile** and forms a covalent intermediate, which lowers the activation energy for the reaction. The enzyme then helps to break the bond and release the product.

Answer 40

1. Nucleophilic reaction between the catalyst and the substrate to form a covalent bond 2. Withdrawal of electrons from the reaction center by the now electrophilic catalyst 3. Elimination of the catalyst, a reaction that is essentially the reverse of stage 1

Answer 41

**Formation of a carbanion:** The decarboxylation of acetoacetate starts with the formation of a carbanion at the carbon adjacent to the carbonyl group (α-carbon). This occurs through the deprotonation of this carbon by a base or through an internal rearrangement. **Elimination of CO₂:** The carbanion formed on the α-carbon is highly unstable and quickly breaks down by the elimination of a carbon dioxide (CO₂) molecule. Formation of acetone: After the elimination of CO₂, the remaining intermediate rearranges to form acetone (CH₃COCH₃), a stable ketone.

Answer 42

In carbonic anhydrase, the residues His94, His119, His96, Thr199, and Glu106 are critical for metal-ion catalysis involving zinc (Zn²⁺). His94, His119, and His96 coordinate the zinc ion, enabling the activation of water molecules to form hydroxide ions, which then nucleophilically attack CO₂ to form bicarbonate. Thr199 stabilises the active site and aids in positioning the substrate, while Glu106 helps deprotonate water molecules and stabilise the transition state. Together, these residues ensure efficient catalysis of the CO₂ to bicarbonate reaction.

Answer 43

Proximity and orientation effects in enzyme catalysis involve bringing substrates together and positioning them in the correct orientation within the enzyme's active site. While simply concentrating substrates can slightly speed up a reaction (up to five times), the real catalytic benefit comes from the enzyme's ability to properly orient the substrates. This alignment minimizes entropy and allows for more efficient bond formation or breaking, greatly reducing activation energy. By restricting substrate motion and ensuring optimal orientation, enzymes can accelerate reactions by up to 10^7 times, making them much more efficient than in solution.

Answer 44

Proline racemase catalyses the **interconversion of D- and L-proline**. It employs two catalytic cysteine residues, which act as general acid-base catalysts, abstracting and donating protons to form a planar carbanion intermediate, the reaction’s transition state. Proline racemase **binds the transition state more tightly than the substrate** (starting molecule) or the product (resulting molecule). This **preferential binding enhances catalytic efficiency** because it lowers the energy barrier of the reaction.

Answer 45

Note: the first 18 codons of chicken lysozyme mRNA are significant as they encode the signal peptide, a short amino acid sequence critical for the protein’s targeting and secretion. Signal peptides are present in many secretory and membrane proteins, and they play a crucial role in directing the nascent protein to the endoplasmic reticulum (ER) for proper processing and transport.

Answer 46

Lysozymes help break down the beta1-4 bonds of piptidoglycans (alternating NAGs and NAMs) which are key components of the bacterial cell wall. This results in the degredation of the bacteria

Answer 47

In the context of the complex with lysozyme, the half-chair structure of the D-ring is crucial for the enzyme's ability to cleave the glycosidic bond in the polysaccharide. The half-chair form of the ring is a transition-state-like structure that helps facilitate the hydrolysis reaction, as it allows for better positioning of the substrate in the active site and promotes the optimal orientation for bond cleavage. The crystal structure provides direct evidence that lysozyme’s active site stabilizes this conformation, enabling the enzyme to effectively catalyze the breakdown of the (NAG)₄ substrate.

Answer 48

- Da = Dalton = molecular mass in g/mol - **Role of E35 (Glutamate-35):** * Glu35 acts as a general acid during catalysis, donating a proton to facilitate the cleavage of the β-(1,4)-glycosidic bond between NAG and NAM. * Substituting Glu35 with glutamine eliminates the carboxylic acid group, rendering it unable to act as a proton donor. - **Role of D52 (Aspartate-52):** * Asp52 serves as a nucleophile, forming a transient covalent intermediate with the substrate during the reaction. * Replacing Asp52 with asparagine removes the negatively charged carboxylate group, preventing nucleophilic attack.

Answer 49

The hydrolytic cleavage of the glycosidic bond by lysozyme is confirmed using isotope labelling with O18-enriched water. During the reaction, the O18 from water is incorporated into the reducing sugar product at its anomeric carbon. Analysis of the product using mass spectrometry or NMR spectroscopy detects the O18 label, providing direct evidence that water participates in the reaction mechanism. This confirms that lysozyme catalyses glycosidic bond hydrolysis and supports the proposed reaction pathway, including the formation of a covalent intermediate in some cases.

Answer 50

**Serine Residues and DIPF (Diisopropylphosphofluoridate):** - Ser195 in enzymes like chymotrypsin is a nucleophilic residue in the active site. DIPF reacts specifically with the hydroxyl group (-OH) of serine residues in the active site to form a stable phosphorylated derivative, thereby inactivating the enzyme. **Histidine Residues and Specific Labelling:** - His57 in serine proteases works alongside Ser195, often as a general base that activates the serine residue by abstracting a proton from its hydroxyl group. - Chemical probes such as N-bromoacetyl derivatives or inhibitors can label histidine residues specifically, helping identify their role in the catalytic mechanism.

Answer 51

The use of **TLCK (trypsin) and TPCK (chemotrypsin) to label histidine** residues and **DIPF to label serine** residues provided crucial evidence for the catalytic triad mechanism in serine proteases (Ser195, His57, and Asp102). These experiments showed how these residues work in concert to facilitate substrate cleavage, with **His57 playing a role in proton transfer and Ser195 acting as the primary nucleophile.** | Since His57 bidning = inactivation, His must be critical for enzyme work

Answer 52

Ser195, Asp102, His57

Answer 53

The oxyanion hole **stabilises the negatively charged oxygen atom that forms during the tetrahedral transition state** in serine proteases. This stabilisation is essential for **lowering the activation energy** of the reaction, thereby enhancing the efficiency of peptide bond cleavage. The oxyanion hole typically involves **hydrogen bonding with the oxygen of the tetrahedral intermediate,** ensuring the reaction proceeds smoothly and rapidly.

Answer 54

v: Reaction rate or rate constant. k: A proportionality constant, often related to the frequency of molecular collisions and orientations. ΔG‡: The Gibbs free energy of activation, which is the energy barrier that must be overcome for the reaction to proceed. R: The universal gas constant (8.314 J mol-1K-1) T: Absolute temperature (in Kelvin). e: The base of the natural logarithm (≈2.718).

Answer 55

The slope of the line = k Halflife (t1/2) = 0.693/k

Answer 56

Typical Michaelis–Menten enzymes follow classical kinetics, where reaction rates (v) depend on substrate concentration ([S]) and exhibit a hyperbolic curve. Their key parameters are Vmax , the maximum reaction rate, and Km , which reflects substrate affinity. These enzymes operate via simple substrate-enzyme interactions without cooperative or allosteric effects, exemplified by enzymes like chymotrypsin and carbonic anhydrase.

Answer 57

The Michaelis constant (Km) is a key parameter in enzyme kinetics that represents the substrate concentration at which an enzyme achieves half of its maximum reaction velocity (Vmax). It provides insight into the enzyme's affinity for its substrate: - A low Km indicates high substrate affinity, as the enzyme reaches half Vmax at low substrate concentrations. - A high Km indicates low substrate affinity, requiring higher substrate concentrations to achieve the same reaction rate. - Km is significant in understanding enzyme efficiency and behaviour under physiological conditions, helping to predict how enzymes function within metabolic pathways and respond to changes in substrate availability.

Answer 58

Therefore, while Km appears to decrease, indicating a stronger binding affinity between the enzyme and substrate, the enzyme’s capacity to convert substrate to product (Vmax) is still reduced, meaning the overall enzymatic activity is lowered, not increased. In summary, uncompetitive inhibition reduces overall enzyme activity by decreasing both the apparent Vmax and Km.