GO:0016402 pristanoyl-CoA oxidase activity: Mechanism, Genes and Research Methods
Research-grade guide for scientists and biopharma professionals
Key Takeaways
• GO:0016402 (pristanoyl-CoA oxidase activity) catalyzes the reaction (2S)-pristanoyl-CoA + O2 = (2E)-pristenoyl-CoA + H2O2, the first step in peroxisomal beta-oxidation of 2-methyl-branched fatty acids [1,2,5].
• The enzyme is a peroxisomal acyl-CoA oxidase that is distinct from palmitoyl-CoA oxidase and trihydroxycoprostanoyl-CoA oxidase, and it is non-inducible by clofibrate in rat liver [3,5].
• Pristanoyl-CoA oxidase shows stereospecific recognition of 2S-methyl-branched acyl-CoA esters, linking it to the degradation of pristanic acid and other 2-methyl-branched substrates.
• A pristanoyl-CoA oxidase gene exists in humans, and enzyme activity is deficient in Zellweger syndrome, a peroxisome biogenesis disorder [6,7].
• The enzyme is used in coupled assays for 2-methylacyl racemase, reflecting its role in the peroxisomal metabolism of 2-methyl-branched fatty acids.
• Research on GO:0016402 benefits from CRISPR knockout, point-mutation, knock-in, overexpression models and functional assays such as enzyme activity, flux analysis and peroxisomal proteomics.
Description
Pristanoyl-CoA oxidase activity (GO:0016402) is a peroxisomal molecular function that catalyzes the desaturation of (2S)-pristanoyl-CoA to (2E)-pristenoyl-CoA with concomitant production of hydrogen peroxide [1,2,5]. This reaction is the initial oxidative step in the peroxisomal beta-oxidation of 2-methyl-branched fatty acids, a pathway that is essential for the breakdown of pristanic acid and related branched-chain substrates [1,5]. The enzyme is one of several acyl-CoA oxidases in peroxisomes, but it is distinguished by its substrate specificity and its non-inducible expression pattern in rat liver [3,5]. The existence of a human pristanoyl-CoA oxidase gene and the deficiency of its activity in Zellweger syndrome underscore its clinical and cell-biological importance [6,7]. Researchers study GO:0016402 to understand peroxisomal fatty acid oxidation, the stereochemistry of 2-methyl-branched acyl-CoA metabolism, and the molecular basis of peroxisomal disorders [4,8].
pristanoyl-CoA oxidase activity At A Glance
| GO ID | GO:0016402 |
|---|---|
| GO term | pristanoyl-CoA oxidase activity |
| Ontology | molecular_function |
| Synonym | (none) |
| Definition | Catalysis of the reaction: (2S)-pristanoyl-CoA + O2 = (2E)-pristenoyl-CoA + H2O2. |
| Major function | Oxidation of pristanoyl-CoA in peroxisomal beta-oxidation of 2-methyl-branched fatty acids. |
| Substrate | (2S)-pristanoyl-CoA |
| Products | (2E)-pristenoyl-CoA and H2O2 |
| Cofactor | FAD (flavin adenine dinucleotide), inferred from acyl-CoA oxidase family biochemistry [1,2]. |
| Cellular location | Peroxisome [1,3,5]. |
| Related enzymes | Palmitoyl-CoA oxidase and trihydroxycoprostanoyl-CoA oxidase [3,5]. |
What Is GO:0016402?
According to the Gene Ontology, pristanoyl-CoA oxidase activity (GO:0016402) is the catalysis of the reaction: (2S)-pristanoyl-CoA + O2 = (2E)-pristenoyl-CoA + H2O2. In other words, it is an oxidoreductase activity that introduces a double bond into the acyl chain of pristanoyl-CoA, using molecular oxygen as the electron acceptor and releasing hydrogen peroxide [1,2,5]. This activity is part of peroxisomal beta-oxidation and acts on 2-methyl-branched acyl-CoA esters with specificity for the 2S-methyl configuration.
Why Is pristanoyl-CoA oxidase activity Important in Cell Biology?
Pristanoyl-CoA oxidase activity is important because it initiates the peroxisomal degradation of 2-methyl-branched fatty acids such as pristanic acid, a pathway that is essential for lipid homeostasis and for preventing the accumulation of branched-chain fatty acids [1,5]. The enzyme is non-inducible by clofibrate, distinguishing it from palmitoyl-CoA oxidase and highlighting distinct regulatory roles among peroxisomal acyl-CoA oxidases. Its stereospecific recognition of 2S-methyl compounds links it to the stereochemistry of branched-chain fatty acid metabolism and to coupled assays for 2-methylacyl racemase [4,8]. In humans, pristanoyl-CoA oxidase activity is deficient in Zellweger syndrome, a severe peroxisomal biogenesis disorder, making this activity a marker of peroxisomal function and a target for understanding peroxisomal disease mechanisms [6,7].
• Initiates peroxisomal beta-oxidation of pristanic acid and other 2-methyl-branched fatty acids [1,5].
• Deficient in Zellweger syndrome, linking the enzyme to peroxisomal biogenesis disorders.
• Distinct from palmitoyl-CoA oxidase and trihydroxycoprostanoyl-CoA oxidase in substrate specificity and regulation [3,5].
• Non-inducible by clofibrate in rat liver, providing a tool to dissect peroxisomal enzyme regulation.
• Shows stereospecific recognition of 2S-methyl-branched acyl-CoA esters.
• Used in coupled enzyme assays for 2-methylacyl racemase, aiding studies of branched-chain fatty acid metabolism.
• A human pristanoyl-CoA oxidase gene exists, supporting translational research.
• Provides a functional readout for peroxisomal fatty acid oxidation in cell and animal models [1,2].
Molecular Mechanism of pristanoyl-CoA oxidase activity
Substrate recognition and binding
In simple terms: The enzyme recognizes a specific branched-chain fat molecule called pristanoyl-CoA.
Pristanoyl-CoA oxidase binds (2S)-pristanoyl-CoA, a 2-methyl-branched acyl-CoA ester, and shows stereospecific recognition of the 2S-methyl configuration. Substrate specificity studies with rat liver peroxisomal acyl-CoA oxidases demonstrate that pristanoyl-CoA oxidase is distinct from palmitoyl-CoA oxidase and trihydroxycoprostanoyl-CoA oxidase, with a preference for 2-methyl-branched substrates. This binding step positions the substrate for oxidation at the alpha,beta-position of the acyl chain [1,2].
Catalytic oxidation and hydrogen peroxide production
In simple terms: The enzyme uses oxygen to create a double bond in the fat molecule and releases hydrogen peroxide.
The catalytic reaction converts (2S)-pristanoyl-CoA and O2 to (2E)-pristenoyl-CoA and H2O2 [1,2,5]. This is a typical acyl-CoA oxidase reaction in which molecular oxygen serves as the electron acceptor and the reduced flavin cofactor is reoxidized, generating hydrogen peroxide [1,2]. The product (2E)-pristenoyl-CoA is then further metabolized by peroxisomal beta-oxidation enzymes [1,5].
Cofactor and flavoprotein nature
In simple terms: The enzyme uses a vitamin-derived helper molecule called FAD to carry electrons.
Pristanoyl-CoA oxidase belongs to the acyl-CoA oxidase family, which are flavoproteins that use FAD as a cofactor [1,2]. The FAD cofactor is reduced during substrate oxidation and reoxidized by molecular oxygen, producing hydrogen peroxide [1,2]. This mechanism is shared with other peroxisomal acyl-CoA oxidases, although substrate specificity differs.
Role in peroxisomal beta-oxidation
In simple terms: This enzyme starts the breakdown of branched-chain fats inside peroxisomes.
Pristanoyl-CoA oxidase catalyzes the first step of peroxisomal beta-oxidation of 2-methyl-branched fatty acids, including pristanic acid [1,5]. The enzyme is localized in peroxisomes and is non-inducible by clofibrate, unlike palmitoyl-CoA oxidase. Its activity is deficient in Zellweger syndrome, reflecting the dependence of peroxisomal beta-oxidation on intact peroxisome biogenesis.
Assay and coupled reactions
In simple terms: Scientists measure this enzyme's activity by coupling it to a color or fluorescence reaction.
Pristanoyl-CoA oxidase is used in a coupled assay for 2-methylacyl racemase, based on the use of pristanoyl-CoA oxidase and peroxidase, to investigate the subcellular distribution of the racemase in rat and human liver. Large-scale purification and characterization of rat pristanoyl-CoA oxidase have enabled detailed kinetic and substrate studies. These assays provide sensitive readouts of peroxisomal branched-chain fatty acid metabolism [2,8].
Key Genes Involved in GO:0016402 pristanoyl-CoA oxidase activity
The following genes and proteins are directly or functionally linked to pristanoyl-CoA oxidase activity (GO:0016402) based on published biochemical and molecular studies.
| Gene | Major Role | Research Relevance |
|---|---|---|
| ACOX1 | Palmitoyl-CoA oxidase, a related peroxisomal acyl-CoA oxidase | Comparative studies of substrate specificity with pristanoyl-CoA oxidase. |
| ACOX2 | Trihydroxycoprostanoyl-CoA oxidase, a related peroxisomal acyl-CoA oxidase | Distinguishing substrate preferences among acyl-CoA oxidases [4,5]. |
| ACOX3 | Pristanoyl-CoA oxidase in rodents; catalyzes oxidation of 2-methyl-branched acyl-CoAs | Direct enzyme for GO:0016402; purification and characterization [2,3,5]. |
| Pristanoyl-CoA oxidase (human gene) | Human ortholog of pristanoyl-CoA oxidase | Evidence for a human gene and its role in peroxisomal metabolism. |
| 2-methylacyl racemase | Converts 2R-methyl-branched acyl-CoAs to 2S forms for oxidation | Coupled assay with pristanoyl-CoA oxidase. |
| Peroxisomal beta-oxidation enzymes (e.g., MFP2, HSD17B4) | Downstream steps of peroxisomal beta-oxidation | Pathway context for pristanoyl-CoA oxidase activity. |
| PEX genes (e.g., PEX1, PEX6) | Peroxisome biogenesis and import | Zellweger syndrome models show deficient pristanoyl-CoA oxidase activity. |
| Catalase | Detoxifies H2O2 produced by acyl-CoA oxidases | Coupled assays and peroxisomal redox balance [2,8]. |
| Peroxidase (assay enzyme) | Used in coupled assays to detect H2O2 | Enables measurement of pristanoyl-CoA oxidase activity. |
| Clofibrate-responsive genes | Inducible peroxisomal enzymes | Contrast with non-inducible pristanoyl-CoA oxidase. |
| Pristanic acid metabolic enzymes | Substrate supply for pristanoyl-CoA oxidase | Links to branched-chain fatty acid catabolism [1,5]. |
| Phytanoyl-CoA hydroxylase | Converts phytanoyl-CoA to pristanoyl-CoA | Provides substrate for pristanoyl-CoA oxidase. |
| ACOX3 (rat) | Non-inducible acyl-CoA oxidase | Model enzyme for GO:0016402 [3,5]. |
| ACOX2 (human) | Trihydroxycoprostanoyl-CoA oxidase | Related activity with overlapping substrate range. |
| FAD-containing oxidases | Flavoprotein family | Mechanistic context for oxygen reduction and H2O2 production [1,2]. |
How Is pristanoyl-CoA oxidase activity Regulated?
Pristanoyl-CoA oxidase activity is regulated at the level of enzyme expression and substrate availability. In rat liver, pristanoyl-CoA oxidase is non-inducible by clofibrate, in contrast to palmitoyl-CoA oxidase, indicating distinct transcriptional regulation among peroxisomal acyl-CoA oxidases. The enzyme acts downstream of phytanoyl-CoA hydroxylase, which produces pristanoyl-CoA, and upstream of other peroxisomal beta-oxidation enzymes, so flux through the pathway depends on substrate supply and peroxisomal import machinery [1,5]. The presence of a human pristanoyl-CoA oxidase gene suggests that expression is controlled by tissue-specific and developmental factors, although detailed regulatory mechanisms remain to be fully defined.
pristanoyl-CoA oxidase activity and Human Disease
| Gene | Disease / Biology | Potential Experimental Model |
|---|---|---|
| ACOX3 | Peroxisomal beta-oxidation deficiency | CRISPR knockout in HepG2 or patient fibroblasts [2,3]. |
| PEX1 | Zellweger syndrome | Patient-derived fibroblasts and CRISPR correction. |
| PEX6 | Zellweger spectrum disorder | Knockout cell models and enzyme activity assays. |
| 2-methylacyl racemase | Branched-chain fatty acid metabolism disorder | Coupled assay with pristanoyl-CoA oxidase. |
| Phytanoyl-CoA hydroxylase | Refsum disease and peroxisomal disorders | Knockout models and substrate flux analysis. |
Zellweger syndrome and peroxisomal biogenesis disorders
Pristanoyl-CoA oxidase activity is deficient in Zellweger syndrome, a severe peroxisomal biogenesis disorder caused by defects in peroxisome assembly. The loss of activity reflects the absence of functional peroxisomes and impaired peroxisomal beta-oxidation of 2-methyl-branched fatty acids. This deficiency contributes to the accumulation of pristanic acid and other branched-chain fatty acids, which are hallmarks of peroxisomal disease [1,7].
Branched-chain fatty acid oxidation defects
Because pristanoyl-CoA oxidase catalyzes the first step in peroxisomal beta-oxidation of 2-methyl-branched acyl-CoAs, defects in this activity or in upstream enzymes can lead to impaired pristanic acid catabolism [1,5]. The stereospecific recognition of 2S-methyl compounds links the enzyme to disorders involving 2-methylacyl racemase and related pathways [4,8]. These defects are studied using enzyme activity assays and coupled reactions that measure pristanoyl-CoA oxidase function [2,8].
Peroxisomal enzyme deficiencies and diagnostic markers
Measurement of pristanoyl-CoA oxidase activity in liver and other tissues can serve as a functional marker of peroxisomal beta-oxidation capacity [3,7]. The non-inducible nature of the enzyme distinguishes it from clofibrate-inducible acyl-CoA oxidases, which is useful for differential diagnosis and for dissecting peroxisomal enzyme regulation. The existence of a human gene supports genetic testing and functional studies in patient-derived cells.
From pristanoyl-CoA oxidase activity-Related Genes to Experimental Models
| Research Question | Suitable Model |
|---|---|
| Does loss of ACOX3 reduce pristanoyl-CoA oxidase activity? | CRISPR knockout in HepG2 or HEK293 cells [2,3]. |
| Does a point mutation in the catalytic domain alter substrate specificity? | Point-mutation knock-in cell lines [4,5]. |
| Can tagged ACOX3 be used to track peroxisomal localization? | Knock-in of fluorescent or affinity tags. |
| Does overexpression of ACOX3 increase pristanic acid oxidation flux? | Overexpression cell models [1,5]. |
| Can CRISPR correction restore activity in Zellweger patient cells? | Patient-derived fibroblasts with PEX gene correction. |
| Does 2-methylacyl racemase cooperate with pristanoyl-CoA oxidase? | Coupled enzyme assays in knockout and overexpression cells. |
How to Study the pristanoyl-CoA oxidase activity Process
| Method | What It Measures | Typical Application |
|---|---|---|
| Coupled peroxidase assay | H2O2 production from pristanoyl-CoA oxidation | Quantifying enzyme activity in cell lysates [2,8]. |
| Substrate specificity assay | Activity with different acyl-CoA esters | Distinguishing pristanoyl-CoA oxidase from other oxidases [4,5]. |
| Subcellular fractionation | Peroxisomal localization | Confirming organelle distribution [1,3]. |
| CRISPR knockout | Loss-of-function effects on activity | Testing gene necessity [2,3]. |
| Point-mutation knock-in | Effect of specific residues on catalysis | Mapping catalytic domain [4,5]. |
| Tagged knock-in | Protein localization and interactions | Imaging and proteomics. |
| Overexpression | Gain-of-function effects on flux | Testing sufficiency in branched-chain fatty acid oxidation [1,6]. |
| Patient cell assays | Enzyme deficiency in disease | Diagnosing Zellweger syndrome. |
Enzyme activity assays
Pristanoyl-CoA oxidase activity is measured using spectrophotometric or fluorometric assays that couple the production of H2O2 to peroxidase and a chromogenic or fluorogenic substrate [2,8]. These assays can be performed on purified enzyme preparations or cell lysates and are used to quantify activity in wild-type and mutant cells [2,5]. Large-scale purification of rat pristanoyl-CoA oxidase has provided standards for such assays.
Substrate specificity and stereochemistry
Substrate specificity studies using various acyl-CoA esters, including 2-methyl-branched compounds, distinguish pristanoyl-CoA oxidase from other peroxisomal acyl-CoA oxidases [4,5]. Stereospecific recognition of 2S-methyl compounds is assessed by comparing activity with 2R and 2S isomers. These methods are essential for assigning enzyme function and for studying racemase-coupled pathways.
Cell and organelle fractionation
Subcellular fractionation and peroxisome isolation are used to confirm the peroxisomal localization of pristanoyl-CoA oxidase and to measure its activity in enriched fractions [1,3,5]. These approaches help distinguish peroxisomal from mitochondrial beta-oxidation and are used in studies of Zellweger syndrome cells. Coupled assays can also be applied to fractionated liver homogenates to investigate racemase distribution.
CRISPR-based functional genomics
CRISPR knockout, point-mutation, knock-in and overexpression models enable causal testing of genes involved in pristanoyl-CoA oxidase activity [2,3,6]. Knockout of ACOX3 or related genes followed by enzyme activity assays can reveal substrate flux changes [2,5]. Knock-in of tagged enzymes allows localization and interaction studies, while overexpression can test gain-of-function effects on branched-chain fatty acid oxidation [1,6].
How CRISPR Can Be Used to Study GO:0016402 pristanoyl-CoA oxidase activity
Knockout
CRISPR knockout of ACOX3 or related genes can abolish pristanoyl-CoA oxidase activity, providing a clean loss-of-function model to test its role in peroxisomal beta-oxidation [2,3]. Knockout cells can be used in coupled enzyme assays to measure residual activity and substrate flux [2,8]. This approach is also useful for validating gene identity in human cells, given the existence of a human pristanoyl-CoA oxidase gene.
Point Mutation
Point mutations in the catalytic domain of pristanoyl-CoA oxidase can be introduced by CRISPR to test the role of specific residues in substrate binding and FAD coordination [4,5]. Such models help dissect stereospecific recognition of 2S-methyl-branched acyl-CoAs. They also enable structure-function studies that complement biochemical purification data.
Knock-in
Knock-in of fluorescent or affinity tags into the endogenous pristanoyl-CoA oxidase gene allows tracking of peroxisomal localization and interaction partners. Tagged knock-in models can be used for imaging and proteomic studies without altering expression levels. This is particularly valuable for studying peroxisomal dynamics in disease models such as Zellweger syndrome.
Overexpression
Overexpression of pristanoyl-CoA oxidase or its human ortholog can increase peroxisomal beta-oxidation flux and provide gain-of-function models [1,6]. These models are useful for testing whether increased enzyme levels enhance pristanic acid catabolism. Overexpression can also be combined with substrate loading to study flux control in peroxisomal pathways [1,8].
How EDITGENE Supports pristanoyl-CoA oxidase activity Research
Researchers studying pristanoyl-CoA oxidase activity-related genes often need to determine whether a candidate gene is causally involved in peroxisomal branched-chain fatty acid oxidation, and CRISPR-based models provide a direct way to test this. EDITGENE offers a suite of gene editing and screening services designed to support such studies from hypothesis to functional validation.
Contact EDITGENE today to design your custom CRISPR model for pristanoyl-CoA oxidase activity research.
Frequently Asked Questions About pristanoyl-CoA oxidase activity
What is pristanoyl-CoA oxidase activity?
Pristanoyl-CoA oxidase activity (GO:0016402) is the catalysis of the reaction (2S)-pristanoyl-CoA + O2 = (2E)-pristenoyl-CoA + H2O2, the first step in peroxisomal beta-oxidation of 2-methyl-branched fatty acids [1,2,5].
What genes are involved in pristanoyl-CoA oxidase activity?
Genes include ACOX3 (pristanoyl-CoA oxidase in rodents), the human pristanoyl-CoA oxidase gene, and related peroxisomal acyl-CoA oxidases such as ACOX1 and ACOX2, as well as 2-methylacyl racemase and peroxisomal beta-oxidation enzymes [2,3,4,5,6,8].
Where does pristanoyl-CoA oxidase act in the cell?
It acts in peroxisomes, where it initiates beta-oxidation of 2-methyl-branched acyl-CoAs [1,3,5].
Is pristanoyl-CoA oxidase inducible by clofibrate?
No, pristanoyl-CoA oxidase is non-inducible by clofibrate in rat liver, unlike palmitoyl-CoA oxidase.
What disease is linked to pristanoyl-CoA oxidase deficiency?
Pristanoyl-CoA oxidase activity is deficient in Zellweger syndrome, a peroxisomal biogenesis disorder.
How is pristanoyl-CoA oxidase activity measured?
It is measured using coupled peroxidase assays that detect H2O2 production from pristanoyl-CoA oxidation [2,8].
Does a human pristanoyl-CoA oxidase gene exist?
Yes, evidence supports the existence of a pristanoyl-CoA oxidase gene in humans.
What is the stereochemistry of pristanoyl-CoA oxidase substrates?
The enzyme shows stereospecific recognition of 2S-methyl-branched acyl-CoA esters.
How is pristanoyl-CoA oxidase related to 2-methylacyl racemase?
Pristanoyl-CoA oxidase is used in a coupled assay for 2-methylacyl racemase, linking the two activities in branched-chain fatty acid metabolism.
What research methods are used to study pristanoyl-CoA oxidase activity?
Methods include enzyme activity assays, substrate specificity studies, subcellular fractionation, and CRISPR knockout, point-mutation, knock-in and overexpression models [2,3,4,5,8].
Conclusion
Pristanoyl-CoA oxidase activity (GO:0016402) is a defined peroxisomal molecular function that catalyzes the oxidation of (2S)-pristanoyl-CoA to (2E)-pristenoyl-CoA with H2O2 production, serving as the entry step for beta-oxidation of 2-methyl-branched fatty acids [1,2,5]. Its distinct substrate specificity, non-inducible regulation and deficiency in Zellweger syndrome make it a valuable marker and research target in peroxisomal biology [3,6,7]. CRISPR-based knockout, point-mutation, knock-in and overexpression models, combined with enzyme activity and flux assays, provide robust tools to dissect its function and regulation [2,4,8].
References
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- 2. Van Veldhoven PP et al.. 1994. Large-scale purification and further characterization of rat pristanoyl-CoA oxidase.. Eur J Biochem 222(3):795-801 PMID: 8026493
- 3. Wanders RJ et al.. 1992. Identification of pristanoyl-CoA oxidase as a distinct, clofibrate non-inducible enzyme in rat liver peroxisomes.. Biochim Biophys Acta 1124(2):199-202 PMID: 1347460
- 4. Van Veldhoven PP et al.. 1996. Peroxisomal beta-oxidation of 2-methyl-branched acyl-CoA esters: stereospecific recognition of the 2S-methyl compounds by trihydroxycoprostanoyl-CoA oxidase and pristanoyl-CoA oxidase.. FEBS Lett 388(1):80-4 PMID: 8654595
- 5. Van Veldhoven PP et al.. 1992. Substrate specificities of rat liver peroxisomal acyl-CoA oxidases: palmitoyl-CoA oxidase (inducible acyl-CoA oxidase), pristanoyl-CoA oxidase (non-inducible acyl-CoA oxidase), and trihydroxycoprostanoyl-CoA oxidase.. J Biol Chem 267(28):20065-74 PMID: 1400324
- 6. Vanhooren JC et al.. 1997. Evidence for the existence of a pristanoyl-CoA oxidase gene in man.. Biochem J 325 ( Pt 3)(Pt 3):593-9 PMID: 9271077
- 7. Wanders RJ et al.. 1990. Identification of pristanoyl-CoA oxidase activity in human liver and its deficiency in the Zellweger syndrome.. Biochem Biophys Res Commun 172(2):490-5 PMID: 2241949
- 8. Van Veldhoven PP et al.. 1997. 2-methylacyl racemase: a coupled assay based on the use of pristanoyl-CoA oxidase/peroxidase and reinvestigation of its subcellular distribution in rat and human liver.. Biochim Biophys Acta 1347(1):62-8 PMID: 9233687
