Term
| collection of enzymes with a common function within a particular organelle or at a specific site in the cell. |
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| What would be some examples of regulation by compounds that bind reversibly in the active site |
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Definition
| the dependence of velocity on substrate concentration and product levels |
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| What would be some examples of regulation by changing the conformation of the active site? |
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Definition
| allosteric regulators, covalent modification, protein–protein interactions, and zymogen cleavage |
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| What would be some examples of regulation by changing the concentration of the enzyme? |
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Definition
| enzyme synthesis and degradation |
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Term
| The velocity of all enzymes is dependent on the |
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Definition
| concentration of the substrate |
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Term
| The approach to the finite limit of Vmax is |
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| The concentration of substrate at which vi equals 1⁄2 Vmax |
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| The rate of the reaction is directly proportional to... |
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| When an enzyme has more than one substrate,the sequence of substrate binding and product release (affect or does not affect) the rate equation. |
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| What depends on the concentration of co-substrate or product present? |
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Term
| What “competes ”with a substrate for binding at the enzyme’s substrate-recognition site and therefore is usually a close structural analog of the substrate? |
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Term
| What can overcome competitive inhibition? |
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Term
| Competitive inhibitors,therefore, (increase/ decrease) the apparent Km of the enzyme (Km, app) because they raise the concentration of substrate necessary to saturate the enzyme. |
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Term
| Do competitive inhibitors have any effect on Vmax? |
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Definition
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Term
| What are compounds that bind to the allosteric site (a site separate from the catalytic site) and cause a conformational change that affects the affinity of the enzyme for the substrate? |
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Definition
| allosteric activators or inhibitors |
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Term
| What is the binding of substrate to one subunit facilitates the binding of substrate to another subunit? |
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Term
| Allosteric effectors are called? |
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Definition
| "K effectors" because they change the Km, but not the Vmax of the enzyme |
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| What is a bulky,negatively charged residue that interacts with other nearby amino acid residues of the protein to create a conformational change at the catalytic site? The conformational change makes certain enzymes more active and other enzymes less active. |
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Term
| These proteins bind to other proteins and regulate their activity by causing a conformational change at the catalytic site or by blocking the catalytic site (steric hindrance)? |
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Term
| What are considered to be the masters of regulation through reversible protein association in the cell? |
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Definition
| G-proteins, they bind and hydrolyze GTP |
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Term
| The precursor proteins of proteases (enzymes that cleave specific peptide bonds) are called? |
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Definition
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Term
| What is the role of the steroid hormone cortisol? |
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Definition
| During fasting or infective stress,protein degradation in skeletal muscle is activated to increase the supply of amino acids in the blood for gluconeogenesis,or for the synthesis of antibodies and other components of the immune response.Under these conditions,synthesis of ubiquitin,a protein that targets proteins for degradation in proteosomes...cortisol increases this |
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Term
| This regulation situation in which the end product of a pathway controls its own rate of synthesis; usually involves allosteric regulation of the rate-limiting enzyme by the end product of a pathway (ora compound that reflects changes in the concentration of the end product). |
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Definition
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Term
| This regulation occurs through an increased supply of substrate to an enzyme with a high Km, allosteric activation of a rate-limiting enzyme through a compound related to substrate supply, substrate-related induction of gene transcription (e.g.,induction of cytochrome P450-2E1 by ethanol), or increased concentration of a hormone that stimulates a storage pathway by controlling enzyme phosphorylation state. |
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