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10 Cards in this Set
- Front
- Back
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How is Mn transported in plasma?
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Bound to transferrin like iron (in Mn3+ state)! However, Mn def. does not result in increased TfRs.
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How is excess Mn excreted?
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Bile: as Mn-billiruben
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How is homeo maintained?
How is it absorbed? |
Via biliary excretion. Not by absorption: only ~ 3-4% absorbed.
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What are some Mn-dependent enzymes?
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Glycosyl transferase
Arginase Pyruvate Carboxylase SOD |
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What is the biochem function of glycosyl transferase?
Activity vs Mn? |
Catalyzes the transfer of sugar to substrate. :
UDP-sugar + substrate --> sugar-substrate + UDP Substrate differs; transferases are specific. Involved in formation of GAGs which are part of the matrix upon which collagen and bone mineral laid down. Decreased Activity w/Low MN |
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What is the biochem function of Arginase?
Activity f(Mn)? Where is this enzyme? |
Hepatic enzyme that is part of urea cycle. High plasma ammonium if low Mn.
Arginine --> urea + ornithine Decreased Activity w/Low MN |
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What is the biochem function of Pyruvate carboxylase?
Activity f(Mn)? Where is this enzyme? |
Mitrochondrial enzyme involved in gluconeogenesis
Pyruvate + HCO3- (+ATP)--> OOA (+ADP + Pi) ****Activity does NOT decrease: Mg substitutes for Mn |
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What is the biochem function of
SOD? Where is this enzyme? |
ONLY mitochrondrial form.
Catalyzed O2- + H --> O2 + H20 & Mn2+-->Mn3+ |
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Mn def in animals?
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Adnormal Lipid Metabolism
Offspring affected: irreversibe ataxia (malformed olith structure), abnormal carb met. Slipped Tendon |
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Toxicity of Mn?
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"Manganese madness" three stages:
1. Abnormal behavior: fatigue, cramps, headage, apathy, psychotic reactions 2. Parkinsonian - monotone voice, loss of expression 3. Abnormal gait, dystonia permanent damage to extrapyramidal system |
