| Term | Definition |
|---|
| Glycogenin | Small protein at center of glycogen granules attached to glycogens reducing end. |
| Glycogen phosphorylase | Major E in glycogen degradation. |
| Glucose-1-P | Major product of Glycogen breakdown. |
| Pyridoxal phosphate | A derivative of vitamin B6. Glycogen phosphorylase acts as a buffer for it as it binds about 80% of body levels. |
| Transferase | Takes 3 of 4 units before branch point and attaches to end of another chain. |
| Debranching Enzyme | Uses glucosidase to hydrolzase 1 remaining unit after transferase act. Chain now smooth and G-phosphorylase can take over again. |
| Phosphoglucomutase | Coverts Glucose 1P to G-6P. Reversible. Needs Glucose 1-6 P2 as cofactor. |
| Glcogen synthase | Adds UDP-glucose to the non-reducing end of the glycogen chain. |
| UDPG pyrophosphorylase | Makes UDPG from G-1-P and UTP. PPi is released. |
| Inorganic pyrophosphatase | Breaks up the PPi released from UDPG pyrophosphorylase allowing glycogen chain to keep growing. |
| Branching enzyme | Removes 7 glucosyl residues from end of chain and attached block in a 1,6 linkage starting another chain. |
| PP1 | Takes phosphate off of Phosphorylase a and converts it back to phosphrylase b. Found on PPlase A until glucose allows it to de P-late a. Then goes to De P-late Glyc. Synthase D back to I. |
| Phosphoralase kinase | Hormonally controls Glycogen phosphorylase. When P-lated, P-lates Glycogen P-lase turning it on. |
| PI cycle | Provides a mechanism for adrenalin to stimulate Ca2+ release in the liver. Ultimately, this causes an (-) of Glycogen synthase and a (+) of P-lase kinase. |
| Alpha adrenalin receptors | Found in liver stimulate PI cycle which starts Ca2+ release and respective effects. |
| cAMP protein kinase a | When P-lated, 1) P-lates P-lase kinase 2) P-lates Glycogen synthase 3) p-lates PP1 (inhibits). |
| Glycogen synthase I | The active form. Sythesizes glycogen. |
| Glycogen synthase D | The inactive form. For synthesis to resume must be de P-lated or must have G6P allosterically bound. |
| Phosphorylase a | The active form. Breaks down glycogen. Has PP-1 bound until glucose stimulates it to de-P-late. |
| Phosphorylase b | The inactive form. Can be turned on when AMP allosterically binds (muscle and liver, but liver would have to be in bad shape for this to happen). |
| Beta adrenalin receptors | Found in liver and muscle. Act similar to glucagon and start pathway from top. |
| Calmodulin | A small calcium binding protein which is needed in muscle p-lase kinase. |
| Von Gierke's Disease | Glucose-6-phosphatase deficiency. |
| G6P-tase deficiency | AKA von gierke's. Causes hepatomegaly, inhibition of glycogen and gluconeogenesis to release glucose in blood. Hypoglycemia, AMP builup—hyperuircemia and lactic acidosis. |
| Allopurinol | Can be used to treat von gierke's disease. Effective gout treatment. |
| Pompe's disease | Alpha 1,4-glucosidase deficiency. Buildup of glycogen in lysosome, bursts, MI. |
| McArdle's disease | Muscle phosphorylase deficiency. Muscle can't get at glycogen stores. |
| Rhabdomyolysis | Tearing of muscle membrane causing myoglobin release, dark urine, and sometimes renal failure. |
| Fructokinase | Brings fructose into cell for metabolism. P-lates at C1 position. |
| Adolase B | Converts F1P into DHAP and Glyceraldehyde. Rate limiting step in fructose metabolism. |
| Triose kinase | P-lates glyceraldehydes to Glyceraldehyde 3P in Fructose metabolism. |
| Essential fructosuria | Caused by defect in liver fructokinase. Fructose peed out or eventually taken up by hexokinase (SLOW). |
| Hereditary fructose intolerance | Deficiency in Aldolase B. Leads to Pi depletion, ATP depletion, hyperuricemia. Blocks gluconeogenesis (inhibits other aldolase) and inhibits p-lase a so no glycogenolysis. |
| Galactokinase | P-lates Galactose and brings into cell. |
| Uridyltransferase | Gal P1 attacks UDP glucose and replaces it. Glucose 1P released for use. |
| UDP-gal 4-epimerase | Changes UDP galactose back into UDP glucose—regenerates carrier. |
| Lactose intolerance | Missing lactase. Lactose builds up, osmotic gradient causes water flux, bacteria use as fuel—gas, H20—diarrhea. |
| Galactosemia with galactokinase deficiency | Galactose builds up in blood. Mild disorder. May cause cataracts. |
| Galactosemia with uridyl transferase deficiency | Carrier can't regenerate so Gal 1P builds up. Pi depletion and related pathology but NO blockage of gluconeogenesis so no systemic lactic acidosis/hypoglycemia. |
| NADPH | Major reductant in biosynthetic pathways. |
| Nonoxidative branch of PPS | Reversible, can work independently, present in almost all tissues. |
| Oxidative branch of PPS | Irreversible, cannot work independently, present in tissues that require NADPH, metabolically controlled. |
| Glucose-6-P dehydrogenase | generates 6-P-gluconolactone and NADPH. 1st E in O2 PPS. |
| Lactonase | Converst 6P gluconolactone to 6P gluconate in 2nd step of O2 PPS. |
| 6-P-gluconate dehydrogenase | 3rd E in O2 PPS. Oxidizes C3, creating Beta ketoacid that rapidly decarboxylates into ribulose 5P. |
| Transketolase | Uses Thiamine pyrophosphate (TPP) as coenzyme to transfer 2-C from Keto sugar-P to top of Aldo sugar-P. |
| Thiamine pyrophosphate | Coenzyme with transketolase. Is an active form of B1 vitamin. |
| Transaldolase | Transfers 3C fragment from keto sugar to aldo sugar. |
| Wernicke-Korsakoff Syndrome | Thiamine deficiency often seen in northern European alcoholics. Transketolase in Non O2 PPS shuts down and neuropsychiatric symptoms occur. |
| Glcose-6-phosphate dehydrogenase deficiency | Seen in blacks and Mediterranean descent. O2 branch of PPS compromised and puts out reduced NADPH. Certain drugs can break already compromised system leading to hemolytic anemia. |
| Pamaquine | Antimalarial drug that purposely stresses red blood cell. Can cause hemolytic anemia in patients with Glucose-6-phosphate dehydrogenase deficiency. |
| Glutathione | Protects cells (especially RBCs) from oxidative damage. Needs NADPH to regenerate from inactive (oxidized) to active (reduced) form. |
| Favism | can cause hemolytic anemia when eating fava beans. Associated with variant of G6PDH. |
| NAQPI | acetaminophen is oxidized by Cytochrom P 450 to this. It reacts with GSH, forms an adduct, and is eliminated from body. |
| N-Acetyl Cysteine | An antimucolytic that's free SH reacts with NAPQI so GSH is not used. |
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