Transaminase

Definition

Transaminases are enzymes that catalyze the transfer of an amino group from an amino acid to a keto acid, forming new amino acids and enabling the interconversion of amino acids and their corresponding carbon skeletons. These enzymes play a critical role in amino acid biosynthesis and protein metabolism by facilitating the synthesis and degradation of amino acids, which are vital for various cellular functions and overall metabolism.

5 Must Know Facts For Your Next Test

1. Transaminases are also known as aminotransferases and include key enzymes like alanine transaminase (ALT) and aspartate transaminase (AST), which are important for assessing liver function.
2. These enzymes are vital for the synthesis of non-essential amino acids, allowing organisms to create amino acids from other nitrogen sources when needed.
3. Transaminases require pyridoxal phosphate (PLP), a derivative of vitamin B6, as a cofactor for their enzymatic activity.
4. The transamination reaction is reversible, meaning it can function in both directions, contributing to both the synthesis and breakdown of amino acids.
5. Altered levels of transaminases in the blood can indicate various health issues, including liver damage, muscle disorders, and metabolic disturbances.

Review Questions

• How do transaminases facilitate the interconversion of amino acids and keto acids in cellular metabolism?
  • Transaminases facilitate this interconversion by catalyzing the transfer of an amino group from an amino acid to a keto acid. This reaction results in the formation of a new amino acid and a new keto acid, allowing cells to adjust their amino acid composition based on metabolic needs. This flexibility is crucial for maintaining protein synthesis and overall nitrogen balance within the cell.
• Discuss the importance of pyridoxal phosphate as a cofactor in the function of transaminases and its relevance to human health.
  • Pyridoxal phosphate (PLP) acts as an essential cofactor for transaminases, enabling them to effectively carry out their role in amino acid metabolism. PLP participates in the catalytic mechanism by forming a temporary bond with the amino group during the transamination process. Since PLP is derived from vitamin B6, deficiencies in this vitamin can lead to impaired transaminase activity, resulting in metabolic imbalances and potential health issues related to protein metabolism.
• Evaluate the implications of altered transaminase levels in clinical settings, particularly regarding liver function tests.
  • Altered transaminase levels can provide critical insights into a patient's liver health. Elevated levels of alanine transaminase (ALT) and aspartate transaminase (AST) are commonly used as markers for liver damage or disease, such as hepatitis or cirrhosis. Understanding these enzyme levels helps healthcare professionals diagnose and monitor liver conditions, guide treatment decisions, and assess the efficacy of therapeutic interventions related to metabolic health.

Related terms

Amino Acids: Organic compounds that serve as the building blocks of proteins, consisting of an amino group, a carboxyl group, and a side chain specific to each amino acid.

Keto Acid: An organic compound that contains a carbonyl group (C=O) adjacent to a carbon atom, which is important in metabolic pathways including amino acid metabolism.

Deamination: The process by which an amino group is removed from an amino acid, leading to the production of ammonia and a corresponding keto acid.