Term
| NADPH and ribonucleosides |
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Definition
Ribonucleosides -> Deoxyribonucleosides
Via Ribonucleotide reductase.
(Active in SH state, inactive = S-S. Oxidized)
Rionucleotide reductase maintained in proper state by thioredoxin reductase.
Uses NADPH |
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Term
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Definition
| Made of Glu(tamate), Cys, Gly Sulfhydral groups on cysteine residues are reduced y NADPH Value of SH group keeps other cysteine groups in reduced states Glutathione reduce these thio groups non-enzymatically |
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Term
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Definition
| Excess S-S bonds may form and produce Heinz bodies Heinz bodies attach to membrane and make it less pliable Leads to RBC removal/hemolysis Glutathione peroxidase requires Se as a cofactor. 2GSH + H202 -> GSSG + H2) Glutathione reductase: GSSG + NADPH -> 2GSH + NADP |
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Term
| Glutathione-S-Transferase |
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Definition
Located in Liver
Attaches glutathione to toxic molecules making them more soluble. |
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Term
| Glutathione and acetaminophen |
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Definition
CYP-450 breaks down acetaminophen into toxic byproduct which is cleared by glutathione.
Too much acetaminophen and glutathione runs out.
HIghly reactive intermediates formed, liver damage within 24-48 hours.
~35% of severe liver failure |
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Term
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Definition
Oxidized Vitc C is recycled by acquiring electrons and H+ from reduced glutathione(GSH)
Vit C is an antioxidant.
Diffusible oxidants -> Reduced(harmless) oxidants |
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Term
| NADPH's role in NO synthesis |
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Definition
L-arginine + O2 + NADPH -> Citrulline + NO + NADP.
Via Ca+ dependent enzyme
NO is vasodilator -> cGMP -> Muscle relaxation.
Viagra inhibits guanylate phosphodiesterase |
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Term
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Definition
NADPH generation in RBC diminished -> Heinz bodies.
May only be symptomatic when drugs are taken.
Fava beans -> Divicine(strong oxidant)
Quinoids -> severe hemolytic anemia only affected males. |
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Term
| G-6-P Deh Deficiency and Malaria |
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Definition
Plasmodium falciparum is sensitive to oxidative damage.
Mutatoin in G-6-P has partially beneficial effect.
Red blood cells die earlier. |
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Term
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Definition
In cytosol uses Zn and Cu to capture superoxide.
In mitochondrira Mn and Cu used to capture superoxide.
Superoxide(O2-) -> H202
Way more enzyme than substrate(super oxide) |
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Term
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Definition
Contains heme and Fe++ in peroxisomes filled with H2O2
1/4 alcohol broken down by catalase, rest by alcohol deh.
Only 1 membrane bi-layer |
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Term
Amyotrophic Lateral Sclerosis(ALS)
Lou Gehrigs disease |
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Definition
Enzyme defect cytosolic superoxide dismutase
REquires Zn and Cu
Neurodegenerative
Motor neurons affeted.
Sensory nerves and ANS remain intact |
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Term
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Definition
Km for FBP is lower than Km for F-1-P F-1-P can accumulate In deficiency: fructose intolerance/ poisoning. F-1-P is trapped in cell. Hypoglycemia, Vomiting, Jaundice
Aldolase B normally: F-1-P -> Glyceraldehyde |
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Term
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Definition
UDP: Glc and derivatives
GDP: Mannose
CMP: Sialic acid - NANA |
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Term
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Definition
Glucose -> sorbitol. Uses NADPH and aldose reductase
Sorbitol + NAD -> NADH + fructorse via sorbitol deh. (active in seminal vesicles)
Fructose by-passes insulin-dependent glut and isomerase rxn.
production of sorbitol favored by high NADPH/NADP |
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Term
| Effects of hyperglycemia on sorbitol metabolism |
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Definition
During hyperglycemia glucose enters, lens, retina, etc.
Water followws sorbitol into cell
Glucose -> sorbitol and is trapped inside cell.
Water retention, retinopathy, cataracts, peripheral nerve damage |
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Term
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Definition
Lactose = dimer of glucos & galactose in B1,4 linkage
Gal + ATP -> Gal-1-P + ADP via galactokinase
UDP-glucose + Gal-1-P -> G-1-P + UDP-galactose via Gal-1-P uridyl transferase. |
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Term
| Gal-1-P uridyl transferase deficiency |
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Definition
UDP-glucose + Gal-1-P -> G-1-P + UDP-galactose.
Galactosemia(similar to fructose intolerance but more tissues affected)
Galactose -> galactitol -> Cataract formation and nerve damage |
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Term
| Functions of UDP-galactose |
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Definition
Important in formation of Lactose
Lactase synthase: Galactosyltransferase and α-lactalbumin.
UDP-Gal + glucose -> Lactose |
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Term
| Regulation of UDP-galactose |
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Definition
Protein A: transferase in most tissues.
UDP-Gal + N-acetylglucosamine -> N-acetyl-lactosamine
Important in structural elements of N-linked(asparigine) glyco proteins
Protein B: α-lactalbumin found only in lactating mammary tissue.
Progesterone inhibits Protein B synthesis
Prolactin stimulates α-lactalbumin synthesis. A/B units combine |
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Term
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Definition
UDP-Glucose -> UDP-glucuronate via UDP-glucose deh
UDP-glucouronate allows glucouronate to be attached and makes compounds polar(soluble)
Important for heme degradation (billirubin is insoluble)
Deficiency of bilirubin-glucuronyl transferase -> Jaundice |
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