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5 Cards in this Set
- Front
- Back
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Define enzyme reactions |
An enzyme is a protein that serves as a biological catalyst that accelerate metabolic reactions by lowering free energy of activation and reduce the time to reach equilibrium. |
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Outline the characteristics of enzyme reactions in terms of efficiency, specificity, activation energy, and equilibrium constant. |
Highly efficient Highly specific Lower free energy of activation Reduce the time to reach equilibrium Does NOT change equilibrium constant (Keq) |
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Define simple vs complex enzymes |
Simple enzymes: composed wholly of proteins
Complex enzymes: composed of proteins and cofactor. The cofactor is called a prosthetic group if it is tightly or covalently bound. The cofactor is called a coenzyme if it is non-covalently bound. Holoenzyme is the protein and its cofactor. An apoenzyme is the protein without its cofactor. |
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Name the six enzyme classes |
1. Oxidoreductases: transfer electrons 2. Transferases: transfer groups 3. Hyrolases: transfer functional group to water 4. Lyases: add groups to double bonds, remove groups to form double bonds 5. Isomerases: transfer groups within molecules to get isomers 6. Ligases: form C-C, C-S, C-O and C-N bonds by condensation reactions coupled to ATP cleavage. |
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Outline the significance of enzymes in clinical practice |
Use in diagnosis: enzymes such as creatinine phosphokinase (CPK), lactose dehydrogenase (LDH), and hydroxybutyric dehydrogenase (HBDH) are used for diagnosis of heart attacks by measuring their amount in blood. Increased amount means heart tissue damage.
Use in treatment of disease: cyclooxygenase produces prostoglandins which cause pain. Administoring aspirin will block or inhibit this enzyme (competitive inhibitor) and thus relieve pain. |
