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| Question | Answer |
| Primary metabolism | important for life |
| Secondary metabolism | less important (xenobiotics often belongs here) |
| What is the goal with metabolism of xenobiotics? | - To make use of a compound or - To facilitate its excretion (which is often done by increases the water solubility of a compound) |
| Phase 1 and 2 of metabolism of xenobiotics | Phase 1: add hydrophilic handle: - Oxidations - Reductions - Hydrolyses Phase 2: add a more hydrophilic ... on the handle: - conjugations |
| What is the most important enzyme for metabolism of xenobiotics | Cytochrome P-450: - (a group of enzymes) - present as a number of isoenzymes - can catalyse oxidations (more common) and reductions (less common) - not unique to humans - highest levels in liver cells - can be induced (Also has cofactors + two enzymes ?) |
| Give an example of a natural function of Cytochrome P-450 | Can oxidaze vitamin E to Calcitriol that regulate Ca uptake |
| ROS | ROS = Reactive Oxygen Species = chemically reactive chemical species containing oxygen |
| How can ROS be generated? | 1. Oxidative metabolism 2. Biotransformation of xenobiotics 3. Ionising radiation |
| Enzymes that degrade ROS | Superoxide dismutase (SOD) Catalase Glutathione peroxidase also vitamins can help |
| Vilket enzym reducerar tillbaka Glutathione peroxidase? | Glutathione disulphide reductase |
| What is some controversy for antioxidants (risks)? | • Phenolics may be antioxidants or prooxidants • Quercetin may decrease glutathione S-transferase activity |
| What is a main risc with ROS? | Lipid peroxidation: • Takes place with unsaturated fatty acids (C=C is a "target" for radicals) |
| Lipid peroxidation | - Membranes are frequently the target for ROS and other radicals - Unsaturated fatty acids are oxidised by radical processes - Membranes and membrane components are damaged - Enzymes on the membrane are damaged Harmful electrophiles are formed |
| The four types of phase I oxidations | 1. Epoxidation of alkenes and aromatics 2. Carbon hydroxylation 3. Heteroatom oxidation 4. Oxidation of alcohols and aldehydes |
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