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AA metabolism
Term | Definition |
---|---|
Important AA metabolism enzymes are | Transaminases, Glutamine synthase, Glutaminase, Glutamate dehydrogenase |
Important coenzymes in Amino acid metabolism are | Pyridoxal phosphate, Tetrahydrofolate (FH4), Tetrahydrobiopterin (BH4) |
Tetrahydrofolate (FH4) is a coenzyme used to | transfer one-carbon groups at various oxidation states. FH4 is used both in amino acid degradation (e.g., serine and histidine) and biosynthesis (e.g,, glycine). |
Tetrahydrobiopterin (BH4) is a cofactor required for | ring hydroxylation reactions (e.g., phenylalanine to tyrosine |
Ketogenic Intermediates are | Acetyl–CoA, Acetoacetyl–CoA |
Glucogenic Intermediates are | 3 phosphoglycerate, Pyruvate, α-Ketoglutarate, Succinyl – CoA, Fumarate, Oxaloacetate |
Almost all of the amino acids that can be synthesized by humans are amino acids used for the synthesis of | additional nitrogen-containing compounds |
Serine can be synthesized from | the glycolytic intermediate phosphoglycerate, which is oxidized, transaminated by glutamate, and dephosphorylated. |
Glycine and cysteine can be derived from | serine. |
Glycine can be produced from serine by a reaction in which | a methylene group is transferred to tetrahydrofolate (FH4) |
Cysteine derives | its carbon and nitrogen from serine. The essential amino acid methionine supplies the sulfur. |
Alanine can be derived by | the transamination of pyruvate. |
Primary hyperoxaluria type 1 results from | a defect in glycine transaminase = accumulation of glycosylate. will form calcium salts in the kidney, leading to stone formation. Renal failure can occur in this disorder |
Homocysteine is a common amino acid from eating meat. High levels of it are linked to | early development of heart disease. It's associated with low levels of vitamins B6, B12, and folate, as well as renal disease |
Cystathionuria, the presence of cystathionine in the urine, is relatively common in | premature infants. In adults, a genetic deficiency of cystathionase.or from a dietary deficiency of pyridoxine (vitamin B6) a cofactor, benign disorder |
Cystinuria is a disorder related to | defective in transport of basic amino acid transporter |
Aspartate can be derived from | oxaloacetate by transamination. |
Asparagine is produced from | aspartate by amidation. |
Glutamine is produced by the | amidation of glutamate. |
Proline and arginine can be derived | from glutamate semi aldehyde , which is formed by the reduction of glutamate. |
Proline can be produced | by the cyclization of glutamate semi aldehyde . |
Arginine, via three reactions of the urea cycle, can be derived from | ornithine, which is produced by the transamination of glutamate semi aldehyde . |
Glutamate is derived from | α-ketoglutarate by the addition of NH4 via the glutamate dehydrogenase reaction or by transamination. |
Glutamine, proline, and arginine can be derived from | glutamate |
Tyrosine (nonessential) is synthesized by hydroxylation of the essential amino acid | phenylalanine in a reaction that requires tetrahydrobiopterin |
When amino acids are degraded the major products are | pyruvate, intermediates of the TCA cycle, acetyl-CoA, and acetoacetate |
Glucogenic amino acid degraded into | Pyruvic acid and intermediates of TCA cycle such as OAA, Alpha keto glutarate, Succinyl CoA, fumarate |
Ketogenic Amino acid degraded as | acetoacetyl CoA and Acetyl CoA |
isoleucine, tryptophan, phenylalanine, and tyrosine are | both glucogenic and ketogenic |
histidine is converted to | formiminoglutamate |
Histidine is essential basic amino acid, responsible for | maximum buffering action |
Histidinemia autosomal recessive disease due to deficiency of histidase leads to accumulation of histidine in | blood, increased imidazole pyruvic acid in urine, clinical features are mental retardation delayed speech |
When there is a deficiency of Folic acid | FIGLU excreated through urine |
Amino acids that form succinyl-CoA | methionine, threonine ,isoleucine and valine |
In maple syrup urine disease | ,the branched-chain alpha-keto acid dehydrogenase the accumulation of alpha-keto analogs leads to neurologic complications. |
Homocystinuria is caused by deficiencies | in he enzymes cystathionine synthase and cystathionine as well as by deficiencies of methyl tetrahydrofolate (CH3-FH4) or of methyl-B12. |
Amino acids that form fumarate | (phenylalanine, tyrosine, and aspartate) |
PKU | Phenylalanine hydroxylase deficient. |
Type I PKU is due to | phenylalanine hydroxylase deficiency. |
Types II and III PKU are due to deficiency of | dihydrobiopterin reductase. |
Type IV and V PKU are due to the deficiency of | the enzyme synthesizing biopterin. |
Tyrosinemia I | Fumarylacetoacetase hydrolase deficient |
Tyrosinemia II | Tyrosine aminotransferase deficient |
Transient Tyrosinemia | immaturity, of hydroxyl phenyl pyruvate dioxygenase , benign, ascorbate supplementation |
Alkaptonuria | Homogenesitate1,2dioxygenase deficient |
Maternal hyperphenylalaninemia is seen in women who do not have proper phenylalanine level control during pregnancy. Infants born to such mothers can have | a variety of disorders including cardiac defects; death may occur in utero. |
Deficiency Forms dark pigment, which discolors the urine and stains the diapers of affected infants. Later in life, the chronic accumulation of this pigment in cartilage may cause arthritic joint pain | Homogentisate oxidase |
Tyrosinase is completely absent | leading to defective synthesis of melanin in Albinism. There will be associated photophobia, nystagmus and decreased visual acuity |
is associated with liver failure, a cabbage like odor, and death within the first year of life. | Tyrosinemia I (also called tyrosinosis) |
lead to lesions of the eye and skin as well as neurologic problems. Patients are treated with a low-tyrosine, low-phenylalanine diet in | Tyrosinemia II |
Hurtnup's disease is | related to transport defects in transporters of neutral amino acid and tryptophane. |
dietary levels of niacin and tryptophan are insufficient, the condition known as | pellagra results. The symptoms of pellagra are dermatitis, diarrhea, dementia, and, finally,death. |
abnormal metabolism of tryptophan occurs in | a vitamin B6 deficiency. produces xanthurenic acid which is excreted in the urine. |
Primary hyperoxaluria type 1 | (glycine) deficient enzyme glycine transaminase, |
Homocystinuria(methionine) deficient enzyme | cystathionine synthase and cystathionine as well as by deficiencies of methyl tetrahydrofolate (CH3-FH4) or of methyl-B12. |
Histidinemia | (histidine) deficient enzyme histidase |