Aminotransferase enzyme dependent on pyridoxal phosphate (null)

Molecular Classification

Enzyme, Transferase, Pyridoxal-phosphate-dependent enzyme

Other Names

PLP-dependent aminotransferase, Pyridoxal 5'-phosphate-dependent aminotransferase, Transaminase (when referring to the class of enzymes)

Disease Roles

Neurological disorders (due to vitamin B6/PLP deficiency)Inborn errors of amino acid metabolism (e.g., primary hyperoxaluria, some forms of epilepsy)Liver disease

Aminotransferase enzyme dependent on pyridoxal phosphate Overview

Aminotransferases dependent on pyridoxal phosphate are a large family of enzymes that catalyze the transfer of an amino group from an amino acid to a keto acid—a process known as transamination. These enzymes require pyridoxal 5'-phosphate (PLP), the active form of vitamin B6, as a coenzyme. PLP acts both as an electron sink and electrophilic catalyst during these reactions by forming a Schiff base with substrate molecules at the enzyme's active site. This enables stabilization and transformation of reaction intermediates critical for biosynthesis and degradation pathways involving most natural amino acids. The activity and specificity depend on both protein structure—especially residues involved in π–π stacking with PLP—and proper binding pocket formation[1][2]. Dysfunction or inhibition can lead to significant metabolic disturbances affecting neurological health, liver function, and overall nitrogen balance in humans[2][3].

Mechanism of Action

Drugs or compounds that inhibit these enzymes typically act by binding to the active site and preventing transamination reactions, often by mimicking substrate or cofactor structure.

Biological Functions

Amino acid metabolism (transamination)

Biosynthesis and degradation of amino acids

Nitrogen metabolism

Electron sink for carbanion stabilization

Disease Associations

Neurological disorders (due to vitamin B6/PLP deficiency)

Inborn errors of amino acid metabolism (e.g., primary hyperoxaluria, some forms of epilepsy)

Liver disease

Safety Considerations

Inhibition can disrupt essential amino acid metabolism.
Vitamin B6 deficiency impairs function, leading to neurological symptoms.
Off-target effects could impact multiple metabolic pathways due to the broad role in amino acid processing.

Interacting Drugs

There are no widely used direct drugs targeting aminotransferases as a therapeutic mechanism, but inhibitors or modulators exist in research settings. Some drugs may affect PLP levels indirectly, such as isoniazid (which can cause vitamin B6 deficiency).

Associated Biomarkers

Biomarker
Elevated serum levels of specific aminotransferases—such as alanine aminotransferase (ALT) and aspartate aminotransferase (AST)—are clinical biomarkers for liver injury or disease.