![\"\"](\"https:\/\/meddists.com\/learn\/wp-content\/uploads\/2021\/12\/AA6.png\")
<\/a>Transamination <\/h2>\n<\/span>\n\n\nThey do not eliminate the nitrogen from the amino acid pool.<\/strong><\/p>\n\n\n\n- Transaminase reactions exist for all amino acids except LYS<\/strong> and THR<\/strong><\/li>
- Transaminases are using pyridoxal phosphate (PLP) as the cofactor of the reaction.<\/li><\/ul>\n\n\n\n
Most frequently used amino acid-keto acid pairs:<\/p>\n\n\n\n
- GLU\/\u03b1-KG (80 % of the cases)<\/li>
- ALA\/PYR; ASP\/OAA<\/li><\/ol>\n\n\n<\/span>\n
Pyridoxal phosphate – PLP<\/strong><\/h2>\n<\/span>\n\n\nPyridoxal phosphate (PLP), is the active form of vitamin B6 and a coenzyme in a variety of enzymatic reactions in the human body. Also, the molecule is called a swiss-knife type, cause it can help in a variety of reactions. <\/p>\n\n\n\n
PLP acts as a coenzyme in all transamination reactions, and in certain decarboxylation, deamination of amino acids. The aldehyde group of PLP forms a Schiff-base linkage with the \u03b5-amino group of a specific lysine group of the aminotransferase enzymes.<\/p>\n\n\n\n
The resulting external aldimine can lose a proton, carbon dioxide, or an amino acid sidechain and become a quinonoid<\/strong> intermediate<\/strong>. <\/p>\n\n\n\nIn transamination, after deprotonation, the quinonoid intermediate accepts a proton at a different position. PLP reacts with GLU, which transfers its alpha-amino group to PLP to make pyridoxamine phosphate (PMP). PMP transfers its nitrogen to the sugar part, making an amino sugar molecule (Figure 2).<\/p>\n\n\n\n![\"\"](\"https:\/\/meddists.com\/learn\/wp-content\/uploads\/2021\/12\/AA7-1024x279.jpg\")
<\/a>Figure 2. PMP and Keto acid formation via PLP SHIFF-base reaction<\/strong><\/figcaption><\/figure>\n\n\n\nPLP is also involved in various beta-elimination reactions such as the reactions carried out by serine dehydratase (Deamination<\/a>).<\/p>\n\n\n<\/span>\nClinical relevance<\/h2>\n<\/span>\n\n\nThe activity of aspartate aminotransferase (AST<\/strong>) in the blood (also called serum glutamate-oxaloacetate transaminase, SGOT<\/strong>) increases in the heart, and alanine aminotransferase (ALT<\/strong>) in the blood (also called serum glutamate-pyruvate transaminase, SGPT<\/strong>) increases in liver diseases.<\/p>\n\n\n\nThe elevated level of the GOT and GPT is a marker of heart attack\/muscle damages or liver diseases like hepatitis or any damage to the liver.<\/p>\n\n\n<\/span>\nReferences<\/h2>\n<\/span>\n\n\nSnider MDS. Devlin\u2019s Textbook of Biochemistry with Clinical Correlations<\/strong>, the 8th Edition. John Wiley & Sons, Incorporated, 2020; 2019.<\/span> <\/p>\n<\/span>
- Transaminase reactions exist for all amino acids except LYS<\/strong> and THR<\/strong><\/li>
- Transaminases are using pyridoxal phosphate (PLP) as the cofactor of the reaction.<\/li><\/ul>\n\n\n\n
Most frequently used amino acid-keto acid pairs:<\/p>\n\n\n\n
- GLU\/\u03b1-KG (80 % of the cases)<\/li>
- ALA\/PYR; ASP\/OAA<\/li><\/ol>\n\n\n<\/span>\n
Pyridoxal phosphate – PLP<\/strong><\/h2>\n<\/span>\n\n\n
Pyridoxal phosphate (PLP), is the active form of vitamin B6 and a coenzyme in a variety of enzymatic reactions in the human body. Also, the molecule is called a swiss-knife type, cause it can help in a variety of reactions. <\/p>\n\n\n\n
PLP acts as a coenzyme in all transamination reactions, and in certain decarboxylation, deamination of amino acids. The aldehyde group of PLP forms a Schiff-base linkage with the \u03b5-amino group of a specific lysine group of the aminotransferase enzymes.<\/p>\n\n\n\n
The resulting external aldimine can lose a proton, carbon dioxide, or an amino acid sidechain and become a quinonoid<\/strong> intermediate<\/strong>. <\/p>\n\n\n\n
In transamination, after deprotonation, the quinonoid intermediate accepts a proton at a different position. PLP reacts with GLU, which transfers its alpha-amino group to PLP to make pyridoxamine phosphate (PMP). PMP transfers its nitrogen to the sugar part, making an amino sugar molecule (Figure 2).<\/p>\n\n\n\n
<\/a>Figure 2. PMP and Keto acid formation via PLP SHIFF-base reaction<\/strong><\/figcaption><\/figure>\n\n\n\n PLP is also involved in various beta-elimination reactions such as the reactions carried out by serine dehydratase (Deamination<\/a>).<\/p>\n\n\n<\/span>\n
Clinical relevance<\/h2>\n<\/span>\n\n\n
The activity of aspartate aminotransferase (AST<\/strong>) in the blood (also called serum glutamate-oxaloacetate transaminase, SGOT<\/strong>) increases in the heart, and alanine aminotransferase (ALT<\/strong>) in the blood (also called serum glutamate-pyruvate transaminase, SGPT<\/strong>) increases in liver diseases.<\/p>\n\n\n\n
The elevated level of the GOT and GPT is a marker of heart attack\/muscle damages or liver diseases like hepatitis or any damage to the liver.<\/p>\n\n\n<\/span>\n
References<\/h2>\n<\/span>\n\n\n
Snider MDS. Devlin\u2019s Textbook of Biochemistry with Clinical Correlations<\/strong>, the 8th Edition. John Wiley & Sons, Incorporated, 2020; 2019.<\/span> <\/p>\n<\/span>
- Transaminases are using pyridoxal phosphate (PLP) as the cofactor of the reaction.<\/li><\/ul>\n\n\n\n