{"id":538,"date":"2017-10-26T14:35:47","date_gmt":"2017-10-26T14:35:47","guid":{"rendered":"https:\/\/courses.lumenlearning.com\/sunynutrition\/?post_type=chapter&p=538"},"modified":"2017-11-13T20:08:33","modified_gmt":"2017-11-13T20:08:33","slug":"6-41-transamination-deamination-ammonia-removal-as-urea","status":"publish","type":"chapter","link":"https:\/\/courses.lumenlearning.com\/suny-herkimer-nutritionflex\/chapter\/6-41-transamination-deamination-ammonia-removal-as-urea\/","title":{"raw":"6.41 Transamination, Deamination & Ammonia Removal as Urea","rendered":"6.41 Transamination, Deamination & Ammonia Removal as Urea"},"content":{"raw":"
\r\n\r\nThe first step in catabolizing, or breaking down, an amino acid is the removal of its amine group (-NH3). Amine groups can be transferred or removed through transamination or deamination, respectively.\r\n\r\nTransamination<\/b>\r\n\r\nTransamination is the transfer of an amine group from an amino acid to a keto acid (amino acid without an amine group), thus creating a new amino acid and keto acid as shown below.\r\n
\r\n\r\n[caption id=\"\" align=\"aligncenter\" width=\"288\"]\"\" Figure 6.411 Generic transamination reaction where the top keto acid is converted to an amino acid, while the bottom amino acid is converted to a keto acid1<\/sup>[\/caption]\r\n\r\n<\/div>\r\nKeto acids and\/or carbon skeletons are what remains after amino acids have had their nitrogen group removed by deamination or transamination. Transamination is used to synthesize nonessential amino acids.\r\n\r\nDeamination<\/b>\r\n\r\nDeamination is the removal of the amine group as ammonia (NH3), as shown below.\r\n
\r\n\r\n[caption id=\"\" align=\"aligncenter\" width=\"800\"]\"\" Figure 6.412 Deamination of cytosine to uracil (nucleotides, not amino acids)2<\/sup>[\/caption]\r\n\r\n<\/div>\r\nThe potential problem with deamination is that too much ammonia is toxic, causing a condition known as hyperammonemia. The symptoms of this condition are shown in the following figure.\r\n
\r\n\r\n[caption id=\"\" align=\"aligncenter\" width=\"652\"]\"\" Figure 6.413 Symptoms of Hyperammonemia3<\/sup>[\/caption]\r\n\r\n<\/div>\r\nOur body has a method to safely package ammonia in a less toxic form to be excreted. This safer compound is urea, which is produced by the liver using 2 molecules of ammonia (NH3) and 1 molecule of carbon dioxide (CO2). Most urea is then secreted from the liver and incorporated into urine in the kidney to be excreted from the body, as shown below.\r\n
\r\n\r\n[caption id=\"\" align=\"aligncenter\" width=\"951\"]\"\" Figure 6.414 Production of urea helps to safely remove ammonia from the body4-6<\/sup>[\/caption]\r\n\r\n<\/div>\r\nReferences<\/b>\r\n\r\n1. http:\/\/en.wikipedia.org\/wiki\/File:Transaminierung.svg\r\n\r\n2. http:\/\/en.wikipedia.org\/wiki\/File:DesaminierungCtoU.png\r\n\r\n3. http:\/\/en.wikipedia.org\/wiki\/File:Symptoms_of_hyperammonemia.svg\r\n\r\n4. http:\/\/commons.wikimedia.org\/wiki\/File:Liver.svg\r\n\r\n5. http:\/\/upload.wikimedia.org\/wikipedia\/commons\/b\/b0\/Kidney_section.jpg\r\n\r\n6. http:\/\/en.wikipedia.org\/wiki\/File:Urea.png\r\n\r\n<\/div>","rendered":"
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The first step in catabolizing, or breaking down, an amino acid is the removal of its amine group (-NH3). Amine groups can be transferred or removed through transamination or deamination, respectively.<\/p>\n

Transamination<\/b><\/p>\n

Transamination is the transfer of an amine group from an amino acid to a keto acid (amino acid without an amine group), thus creating a new amino acid and keto acid as shown below.<\/p>\n

\n
\"\"<\/p>\n

Figure 6.411 Generic transamination reaction where the top keto acid is converted to an amino acid, while the bottom amino acid is converted to a keto acid1<\/sup><\/p>\n<\/div>\n<\/div>\n

Keto acids and\/or carbon skeletons are what remains after amino acids have had their nitrogen group removed by deamination or transamination. Transamination is used to synthesize nonessential amino acids.<\/p>\n

Deamination<\/b><\/p>\n

Deamination is the removal of the amine group as ammonia (NH3), as shown below.<\/p>\n

\n
\"\"<\/p>\n

Figure 6.412 Deamination of cytosine to uracil (nucleotides, not amino acids)2<\/sup><\/p>\n<\/div>\n<\/div>\n

The potential problem with deamination is that too much ammonia is toxic, causing a condition known as hyperammonemia. The symptoms of this condition are shown in the following figure.<\/p>\n

\n
\"\"<\/p>\n

Figure 6.413 Symptoms of Hyperammonemia3<\/sup><\/p>\n<\/div>\n<\/div>\n

Our body has a method to safely package ammonia in a less toxic form to be excreted. This safer compound is urea, which is produced by the liver using 2 molecules of ammonia (NH3) and 1 molecule of carbon dioxide (CO2). Most urea is then secreted from the liver and incorporated into urine in the kidney to be excreted from the body, as shown below.<\/p>\n

\n
\"\"<\/p>\n

Figure 6.414 Production of urea helps to safely remove ammonia from the body4-6<\/sup><\/p>\n<\/div>\n<\/div>\n

References<\/b><\/p>\n

1. http:\/\/en.wikipedia.org\/wiki\/File:Transaminierung.svg<\/p>\n

2. http:\/\/en.wikipedia.org\/wiki\/File:DesaminierungCtoU.png<\/p>\n

3. http:\/\/en.wikipedia.org\/wiki\/File:Symptoms_of_hyperammonemia.svg<\/p>\n

4. http:\/\/commons.wikimedia.org\/wiki\/File:Liver.svg<\/p>\n

5. http:\/\/upload.wikimedia.org\/wikipedia\/commons\/b\/b0\/Kidney_section.jpg<\/p>\n

6. http:\/\/en.wikipedia.org\/wiki\/File:Urea.png<\/p>\n<\/div>\n\n\t\t\t

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Candela Citations<\/h3>\n\t\t\t\t\t
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