GPT: Alanine Transaminase (Glutamic–Pyruvic Transaminase)
Key enzyme in amino acid metabolism and clinical biomarker for liver health
Gene Information Card
| Symbol | GPT |
|---|---|
| Full Name | Glutamic–Pyruvic Transaminase |
| Gene Type | Protein coding |
| Chromosomal Location | 8q24.3 |
| NCBI Gene ID | 2875 ncbi.nlm.nih.gov/gene/2875 |
| Ensembl ID | ENSG00000167701 |
| UniProt ID | P24298 |
| OMIM ID | 138200 |
| HGNC ID | 4552 |
| Aliases | ALT1, GPT1, AAT1, ALAT1 |
Description
The GPT gene encodes alanine transaminase (ALT), a pyridoxal phosphate-dependent enzyme that catalyzes the reversible transamination between alanine and 2-oxoglutarate to form pyruvate and glutamate. ALT is primarily expressed in the liver and is a key clinical biomarker for hepatocellular injury; elevated serum ALT levels are used to diagnose and monitor liver diseases such as hepatitis, cirrhosis, and drug-induced liver injury.
Disease Associations
| Disease category | Pathophysiological mechanism | Genomic evidence |
|---|---|---|
| Alanine transaminase deficiency | Loss-of-function mutations in GPT lead to reduced ALT activity, causing elevated serum alanine and susceptibility to metabolic disturbances. | OMIM #138200, case reports |
| Liver disease (elevated ALT) | Hepatocellular injury releases ALT into bloodstream; GPT polymorphisms may influence baseline ALT levels and disease susceptibility. | ClinVar, GWAS studies |
| Type 2 diabetes | GPT variants associated with altered alanine metabolism and insulin resistance. | OMIM, population studies |
Expression Profile
Tissue Expression
| Tissue | nTPM | level |
|---|---|---|
| Liver | 18.5 | High |
| Kidney | 4.2 | Medium |
| Heart | 2.1 | Low |
| Skeletal muscle | 1.8 | Low |
| Pancreas | 1.5 | Low |
Cell Line Expression
| Cell Line | nTPM | Notes |
|---|---|---|
| HepG2 | 22.3 | Liver cancer cell line, high expression |
| HEK293 | 3.1 | Embryonic kidney, moderate |
| K562 | 0.9 | Leukemia, low |
Data source：Human Protein Atlas（proteinatlas.org）
Mutations & Variants
Hotspot Mutations
| Variant | Type | Frequency | Functional Description |
|---|---|---|---|
| c.499G>A (p.Gly167Arg) | Missense | <0.1% | Reduced enzyme activity, associated with ALT deficiency |
| c.925G>A (p.Glu309Lys) | Missense | <0.1% | Impaired catalytic function |
| c.1061C>T (p.Pro354Leu) | Missense | <0.1% | Decreased stability and activity |
Mutation functional classification
Loss of Function (LOF)
Missense mutations (e.g., p.Gly167Arg, p.Glu309Lys) reduce or abolish ALT enzymatic activity, leading to alanine transaminase deficiency.
Gain of Function (GOF)
No gain-of-function mutations reported in GPT.
Dominant Negative (DN)
No dominant-negative mutations reported; GPT is a homodimer, but dominant effects are not documented.
View complete mutation data：
Gene Ontology (GO)
| • alanine transaminase activity (GO:0004020) | • biosynthetic process (GO:0009058) |
| • cellular amino acid metabolic process (GO:0006520) | • cytoplasm (GO:0005737) |
| • cytosol (GO:0005829) |
Pathways
• Alanine and aspartate metabolism (KEGG: hsa00250)
• Pyruvate metabolism (KEGG: hsa00620)
• Metabolic pathways (KEGG: hsa01100)
Protein Summary
Alanine transaminase (ALT) is a homodimeric cytosolic enzyme of 496 amino acids (molecular weight ~54 kDa). It requires pyridoxal phosphate as a cofactor and catalyzes the reversible transfer of an amino group from alanine to 2-oxoglutarate, producing pyruvate and glutamate. ALT is highly expressed in the liver and, to a lesser extent, in kidney, heart, and skeletal muscle. Its primary physiological role is in gluconeogenesis and amino acid metabolism. Clinically, serum ALT is a sensitive marker for hepatocyte damage.
Related Services
Related Products
| Product name | Cat.No. | Species | Gene ID | |
|---|---|---|---|---|
| GPT Knockout HEK293 Cell Line | EDJ-KQ3492 | Human | 2875 | Details Get a Quote |
| GPT2 Knockout HEK293 Cell Line | EDJ-KQ10175 | Human | 84706 | Details Get a Quote |
| GPT2 Knockout A-549 Cell Line | EDJ-KQ37286 | Human | 84706 | Details Get a Quote |
| GPT2 Knockout HCT 116 Cell Line | EDJ-KQ37287 | Human | 84706 | Details Get a Quote |
| GPT2 Knockout HeLa Cell Line | EDJ-KQ37288 | Human | 84706 | Details Get a Quote |
| GPT Knockout HeLa Cell Line | EDJ-KQ53414 | Human | 2875 | Details Get a Quote |
| GPT Knockout A-549 Cell Line | EDJ-KQ61890 | Human | 2875 | Details Get a Quote |
| GPT Knockout HCT 116 Cell Line | EDJ-KQ70370 | Human | 2875 | Details Get a Quote |
