الفريق الطبي األكاديمي لكية الطب البرشي البلقاء التطبيقية / املركز 2022 2016/
-the ones with * are the essential amino acids- - Histidine decarboxylation -> histamine Page 1
- Glutamine is a nitrogen carrier in the peripheral tissues, because it is neutral and nontoxic and can cross the BBB easily. - 18 of the amino acids can enter the transamination reaction (but the lysine and threonine) Page 2
- Methionine is an essential amino acid. Cysteine (a product of methionine metabolism) is a nonessential. - The importance of methionine metabolism is forming S-Adenosylmethionine, and then by transmethylation, S-Adenosylhomocysteine is formed. By removing Adenosine, the S-Adenosylhomocysteine becomes Homocysteine. Serine is added, the Cystathionine is formed, finally with the removal of a-ketobutyrate and ammonia, the final product (Cysteine) is formed. *Homocysteine is important for atherosclerosis and cardiac diseases. Page 3
- An active methyl group is forms S-Adenosylhomocysteine, and by hydration, homocysteine is formed. - Homocysteine is important for heart diseases, like myocardial infarction. (Diseases indicator or marker) Page 4
- Aromatic amino acids: tyrosine, phenylalanine, tryptophan. (the three of them are ketogenic and glucogenic). Page 5
- Phenylalanine will accumulate in the body. - This disease causes mental retardation and growth problems, and it could lead to death if it was not well treated. - Amino acids analyzer measures 20 amino acids concentrations, giving indication for each amino acid, and its level. After birth, this analysis is directly made, to reveal any deficiency or disease like phenylketonuria. The same happens with glucose-6-phosphate dehydrogenase deficiency, this deficiency is also scanned after birth directly, because this deficiency may lead to anemia. - Galactosemia: galactose metabolism deficiency which cause mental retardation. - Thyroid hormone, is also measured after birth. - Belly robin test (liver diseases), done after birth too. (Five tests are done after birth.) Page 6
- Normal pathways (phenylalanine -> tyrosine -> melanin -> tissue protease -> catecholamines -> fumarate and acetoacetate) are blocked. When there is a deficiency of the phenylalanine hydroxylase (phenylalanine will not give tyrosine), phenylalanine will accumulate, and tyrosine will be minimal because the pathway that synthesizes it is blocked. Accumulation of phenylalanine gives, phenyl pyruvate, phenyl acetate, and those will be the major products in the blood, and then will be eliminated with the urine. That is why it is called phenylketonuria (increasing of phenylalanine products in urine). Page 7
- Phenylketonuria treatment: special diets containing free of phenylalanine. Food like vegetarian milk (soymilk, rice milk), is given to the patient instead of regular milk (animal source milk). - When it is accumulated in the body, it gives black color to the urine. (Auto oxidation) Page 8
- Only two amino acids are ketogenic (leucine and myosin). - Isoleucine: (ketogenic and glucogenic) ->acetyl CoA ->propionyl CoA - Anything enters the citric acid cycle as an intermediate -> glucogenic. Because it will end up as oxaloacetate which gives glucose, through gluconeogenesis. Page 9
- If a deficiency happened to the oxidative decarboxylation, it will cause a disease called (Mable syrup urine disease). Because of the accumulation of the branched chained amino acids, the urine smell like Mable tree. This deficiency causes mental retardation. Page 10
- Tryptophan is a glucogenic and ketogenic. - Alanine is glucogenic. - Acetoacetate is ketogenic. Page 11
- Histidine decarboxylation gives Histamine, and at the end, glutamate. * Glutamate is important as a neurotransmitter of the brain. - Succinyl CoA is an intermediate of the citric acid cycle. Page 12
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- Cystinuria: deficit of the cysteine absorption in kidney. Causing formation of stones in the kidney (calcium oxalate, calcium carbonate, uric acid and cysteine) Thank You. Page 14