CA5B Gene - Carbonic Anhydrase 5B
Mitochondrial Carbonic Anhydrase VB: Function, Expression, and Disease Associations
Gene Information Card
| Symbol | CA5B |
|---|---|
| Full Name | Carbonic anhydrase 5B |
| Gene Type | Protein coding |
| Chromosomal Location | Xp22.2 |
| NCBI Gene ID | 7157 ncbi.nlm.nih.gov/gene/7157 |
| Ensembl ID | ENSG00000169239 |
| UniProt ID | Q9Y2D0 |
| OMIM ID | 300230 |
| HGNC ID | 1379 |
| Aliases | CA-VB, CA5B_HUMAN, carbonic anhydrase VB |
Description
The CA5B gene encodes carbonic anhydrase 5B, a mitochondrial isozyme of the carbonic anhydrase family. This enzyme catalyzes the reversible hydration of carbon dioxide to bicarbonate and protons, playing a critical role in mitochondrial metabolism, particularly in gluconeogenesis, ureagenesis, and lipogenesis. CA5B is expressed in various tissues, with highest levels in the liver, kidney, and pancreas. Mutations in CA5B are associated with hyperammonemia and metabolic acidosis.
Disease Associations
| Disease category | Pathophysiological mechanism | Genomic evidence |
|---|---|---|
| Hyperammonemia due to carbonic anhydrase VA deficiency | Loss-of-function mutations in CA5B impair mitochondrial bicarbonate production, disrupting the urea cycle and leading to ammonia accumulation. | ClinVar; OMIM #300230 |
| Carbonic anhydrase VA deficiency | Biallelic pathogenic variants in CA5B cause a metabolic disorder characterized by hyperammonemia, metabolic acidosis, and developmental delay. | OMIM; PMID: 25683116 |
Expression Profile
Tissue Expression
| Tissue | nTPM | level |
|---|---|---|
| Liver | 12.3 | Medium |
| Kidney | 8.7 | Medium |
| Pancreas | 6.5 | Medium |
| Brain | 2.1 | Low |
| Heart | 1.8 | Low |
| Skeletal muscle | 0.9 | Not detected |
Cell Line Expression
| Cell Line | nTPM | Notes |
|---|---|---|
| HepG2 | 10.5 | Hepatocellular carcinoma cell line |
| HEK293 | 4.2 | Embryonic kidney cells |
| MCF7 | 1.1 | Breast cancer cell line |
| A549 | 0.8 | Lung carcinoma cell line |
Data source：Human Protein Atlas（proteinatlas.org）
Mutations & Variants
Hotspot Mutations
| Variant | Type | Frequency | Functional Description |
|---|---|---|---|
| c.1A>G (p.Met1?) | Missense | Rare | Loss of start codon, likely loss of function |
| c.232C>T (p.Arg78Trp) | Missense | Rare | Impaired enzyme activity |
| c.497G>A (p.Arg166Gln) | Missense | Rare | Reduced catalytic efficiency |
Mutation functional classification
Loss of Function (LOF)
Pathogenic missense and nonsense mutations in CA5B lead to reduced or absent carbonic anhydrase activity, impairing mitochondrial bicarbonate supply and causing hyperammonemia.
Gain of Function (GOF)
No gain-of-function mutations reported for CA5B.
Dominant Negative (DN)
No dominant-negative mutations reported for CA5B.
View complete mutation data：
Gene Ontology (GO)
| • carbonate dehydratase activity | • zinc ion binding |
| • mitochondrion | • one-carbon metabolic process |
| • bicarbonate transport |
Pathways
• Urea cycle
• Gluconeogenesis
• Lipogenesis
• Nitrogen metabolism
Protein Summary
Carbonic anhydrase 5B (CA-VB) is a 317-amino acid mitochondrial enzyme that catalyzes the reversible hydration of CO2 to HCO3- and H+. It is essential for providing bicarbonate for the urea cycle and gluconeogenesis. The protein contains a zinc-binding active site and is localized to the mitochondrial matrix. Defects in CA5B cause hyperammonemia due to carbonic anhydrase VA deficiency.
Related Services
Related Products
| Product name | Cat.No. | Species | Gene ID | |
|---|---|---|---|---|
| CA5B Knockout HEK293 Cell Line | EDJ-KQ7342 | Human | 11238 | Details Get a Quote |
| SPACA5B Knockout HEK293 Cell Line | EDJ-KQ15422 | Human | 729201 | Details Get a Quote |
| CA5B Knockout HeLa Cell Line | EDJ-KQ31071 | Human | 11238 | Details Get a Quote |
| CA5B Knockout A-549 Cell Line | EDJ-KQ32444 | Human | 11238 | Details Get a Quote |
| CA5B Knockout HCT 116 Cell Line | EDJ-KQ32445 | Human | 11238 | Details Get a Quote |
| SPACA5B Knockout HeLa Cell Line | EDJ-KQ60733 | Human | 729201 | Details Get a Quote |
| SPACA5B Knockout A-549 Cell Line | EDJ-KQ69203 | Human | 729201 | Details Get a Quote |
| SPACA5B Knockout HCT 116 Cell Line | EDJ-KQ77560 | Human | 729201 | Details Get a Quote |
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