Question | Answer |
Lecture 50 | Water Soluble Vitamins III, Trace Minerals |
___ is an essential part of coenzyme A. | Pantothenic acid |
Pantothenic acid deficiency is rare, and leads to ___. | burning foot syndrome |
Biotin deficiency leads ___ around the openings. | rashes |
Mammals can do ___ fixation. | carbon dioxide |
Mammals cannot do ___ fixation. | net carbon dioxide |
Biotin + ATP → | Biotinyl-AMP + Apocarboxylase, catalyzed by biotinyl-AMP synthetase |
Biotinyl-AMP + Apocarboxylase → | Holocarboxylase, catalyzed by holocarboxylase synthase |
Holocarboxylase synthase deficiency: | similar to biotin deficiency, unable to fix biotin to apocarboxylase, increased organic acid excretion |
3-Methylcrotonyl-CoA carboxylase deficiency: | isovaleryl-CoA to 3-HIA, 3-methylcrotonyl-CoA to 3-MCG |
Propionyl-CoA carboxylase deficiency: | propionyl-CoA to 3-OH propionate, propionylglycine, and methylcitrate |
Propionyl-CoA buildup can lead to substitution of acetyl-CoA in TCA to form ___. | methylcitrate |
Propionyl-CoA carboxylase activity ___ in biotin deficiency. | decreases |
Propionyl-CoA carboxylase activation coefficient ___ in biotin deficiency. | increases |
Biotinidase | Catalyzes cleavage of E-biotin to biotin and peptides, so biotin can be absorbed |
Biotinidase deficiency: | leads to biotin deficiency due to malabsorption |
Dietary iron is ___ absorbed. | poorly |
___ is the best absorbed formed of iron. | Fe2+ |
___ reclaims Fe. | Macrophages |
Vitamin C ___ iron absorption. | increases |
Increased demand for iron during: | menstruation, pregnancy, and growth |
Ferritin | Intracellular Fe binding protein, 24 subunits, 4500 Fe3+ atoms in ferritin |
Transferrin | Coded by TF gene, transports Fe from intestine to tissues/bone marrow |
Total Iron Binding Capacity (TIBC) | Measures transferrin and its ability to carry iron in blood |
Percent Transferrin Saturation | Low <10%, Normal =30%, High >60% |
Hemosiderin | Iron overload, amorphous glops (hemosiderin) form around ferritin |
Vitamin C assists in Fe absorption by: | reduction of Fe3+ to Fe2+, catalyzed by ferrireductase |
Fe2+ is absorbed by: | DMT-1 |
Fe2+reoxidized to Fe3+ in the enterocyte and stored in ___. | ferritin |
Ferroportin exports the ___ form of Fe. | Fe2+ (Fe3+ in ferritin must be reduced to be exported) |
Hepcidin ___ ferrorportin. | inhibits |
Fe homeostasis occurs primarily at the ___. | intestine |
Loss-of-function mutation in ferroportin causes ___. | iron deficiency anemia |
Loss-of-interaction of ferrorportin with hepcidin causes ___. | iron toxicity (iron overload), hemosiderin, hemochromatosis |
___ inhibits the binding of transferrin-Fe3+ to TfR1 cell surfaces, which leads to incorporation of Fe into the cell. | Hfe |
Hfe deficiency leads to: | secondary hemochromatosis (Fe overload) |
Zinc is a cofactor to > ___ enzymes. | 300 |
Zinc Fingers | Zn2+ coordinated with 4 amino acid residues, transcription factor/nuclear hormone receptor/signal transduction |
Enzymatic reactions zinc is a coenzyme for: | metabolis, protein degradation/synthesis, fatty acid synthesis, nucleic acid synthesis, heme synthesis, oxidative damage protection |
Zinc deficiency: | agnosia, anorexia, rash, impaired healing, exocrine/endocrine pancreatic function (diarrhea/glucose tolerance), spermatogenesis, DNA replication (growth retardation) |
Acrodermatitis Enteropathica | Inherited Zn malabsorption, severe skin rash, diarrhea, alopecia |
Causes of zinc deficiency: | severe burns, GI diseases, increased loss with albumin (nephrotic syndrome, dialysis), IV feeding, stress |
Serum zinc measurement affected by: | inflammation, stress, cancer, smoking, steroid, hemolysis |
Copper deficiency is rare, and can occur by: | reduced intake (extended high fiber diet) and excess loss (dialysis) |
Copper deficiency: | microcytic hypochromic anemia, neutropenia, collagen degeneration, skin depigmentation, hypercholesterolemia |
Menke’s Syndrome | Inherited Cu transport deficienc, alteration in hair structure |
Copper toxicity: | hemolysis, liver and brain cell damage |
Wilson’s Disease | ATP7B defective copper excretion from cells, chronic accumulation, liver failure/CNS dysfunction |
Selenium is involved in ___ and ___. | selenocysteine and selenomethionine |
Selenium is a cofactor for: | selenoprotein P & W, glutathione peroxidase |
Selenoprotein P & W | Protection from oxidative damage, Se delivery |
Keshan Disease | Se deficiency cardiomypathy |