GO:0000096 sulfur amino acid metabolic process: Pathway, Genes, Functions and Research Methods
Research-grade guide for scientists and biopharma professionals
Key Takeaways
• GO:0000096 sulfur amino acid metabolic process describes the chemical reactions and pathways involving amino acids that contain sulfur, including methionine, cysteine, homocysteine, and cystine.
• The pathway is central to one-carbon metabolism, redox homeostasis, and coenzyme A synthesis, linking dietary sulfur amino acid intake to hepatic metabolic adaptation.
• Dietary sulfur amino acid restriction (SAAR) alters the plasma and urine sulfurome and correlates with loss of fat mass and adipose tissue gene expression in humans with overweight and obesity.
• SAAR activates the integrated stress response and improves glucose homeostasis through hepatic de novo serine synthesis.
• Dysregulation of sulfur amino acid metabolism is implicated in leukemia and is being explored as a therapeutic target.
• Mammalian sulfur amino acid metabolism is subject to extensive posttranslational regulation, making it a rich area for CRISPR-based functional genomics.
Description
Sulfur amino acid metabolic process (GO:0000096) is the biological process comprising the chemical reactions and pathways involving amino acids that contain sulfur. These amino acids, principally methionine and cysteine, are indispensable for protein synthesis, one-carbon transfer, redox balance, and the biosynthesis of coenzyme A and other sulfur-containing metabolites. The term is a core node in amino acid metabolism and is conserved from parasitic protozoa to humans. Understanding this process is essential because sulfur amino acid availability and flux influence diverse physiological outcomes, from hepatic metabolic adaptation to adipose tissue biology and glucose homeostasis. In humans, dietary sulfur amino acid restriction has emerged as a nutritional strategy that reshapes the plasma and urine sulfurome and is associated with loss of fat mass. At the same time, the pathway is a recognized vulnerability in leukemia, where targeting sulfur-containing amino acid metabolism is under active investigation. The process is also tightly regulated at the posttranslational level, adding layers of complexity that are only now being resolved. For researchers, GO:0000096 provides a structured framework to interrogate how sulfur amino acid flux is sensed, regulated, and rewired in disease, and to design CRISPR-based models that test causal roles of individual enzymes and transporters.
sulfur amino acid metabolic process At A Glance
| GO ID | GO:0000096 |
|---|---|
| GO term | sulfur amino acid metabolic process |
| Ontology | biological_process |
| Synonym | sulfur amino acid metabolism; sulphur amino acid metabolic process; sulphur amino acid metabolism |
| Definition | The chemical reactions and pathways involving amino acids containing sulfur. |
| Major function | Synthesis, interconversion, and degradation of sulfur-containing amino acids such as methionine and cysteine, supporting one-carbon metabolism, redox homeostasis, and coenzyme A production. |
| Key substrates | Methionine, cysteine, homocysteine, cystine, and related sulfur-containing intermediates. |
| Physiological relevance | Dietary sulfur amino acid restriction alters the sulfurome and correlates with fat mass loss and adipose gene expression changes. |
| Disease link | Implicated in leukemia and explored as a therapeutic target. |
| Regulation | Subject to posttranslational regulation in mammals. |
What Is GO:0000096?
GO:0000096 sulfur amino acid metabolic process is defined by the Gene Ontology as the chemical reactions and pathways involving amino acids containing sulfur. In practice, this encompasses the synthesis, interconversion, and degradation of sulfur-containing amino acids such as methionine, cysteine, homocysteine, and cystine, as well as the metabolic routes that transfer sulfur between them and into downstream products like coenzyme A and glutathione precursors. The term is a biological process and is synonymous with sulfur amino acid metabolism and sulphur amino acid metabolic process.
Why Is sulfur amino acid metabolic process Important in Cell Biology?
Sulfur amino acid metabolic process is important because it sits at the intersection of nutrition, redox biology, and metabolic disease. Dietary sulfur amino acid restriction in humans with overweight and obesity produces a distinct plasma and urine sulfurome signature that correlates with loss of fat mass and changes in adipose tissue gene expression. The pathway is also a therapeutic vulnerability in leukemia, where targeting sulfur-containing amino acid metabolism is being actively pursued. In the liver, TFEB regulates sulfur amino acid and coenzyme A metabolism to support metabolic adaptation and redox homeostasis. Moreover, the integrated stress response is mechanistically linked to dietary sulfur amino acid restriction, and SAAR improves glucose homeostasis through hepatic de novo serine synthesis. These findings position GO:0000096 as a high-value target for metabolic, oncological, and nutritional research.
• Provides methionine and cysteine for protein synthesis and one-carbon metabolism.
• Supports redox homeostasis through cysteine-derived antioxidants such as glutathione precursors.
• Links dietary sulfur amino acid intake to adipose tissue biology and fat mass regulation.
• Is a metabolic vulnerability in leukemia and a candidate for targeted therapy.
• Is regulated by TFEB to support hepatic metabolic adaptation and coenzyme A metabolism.
• Is subject to posttranslational regulation, offering many entry points for functional studies.
• Dietary sulfur amino acid restriction activates the integrated stress response.
• SAAR improves glucose homeostasis via hepatic de novo serine synthesis.
• Conserved across parasitic protozoa, informing antiparasitic drug discovery.
• Underpins human sulfur amino acid requirements and nutritional guidelines.
What Happens During sulfur amino acid metabolic process?
Methionine acquisition and transmethylation
In simple terms: The body obtains methionine from diet and recycles it through a cycle that donates methyl groups.
Methionine is an essential sulfur amino acid that enters the pathway from dietary protein or from remethylation of homocysteine. It serves as the principal methyl donor via S-adenosylmethionine, and its demethylation yields homocysteine, which can be remethylated to methionine or directed toward cysteine synthesis. In humans, dietary sulfur amino acid restriction alters the plasma and urine sulfurome, reflecting changes in methionine and related metabolite flux.
Transsulfuration and cysteine synthesis
In simple terms: Homocysteine can be converted into cysteine, a sulfur amino acid used in many protective molecules.
The transsulfuration pathway converts homocysteine to cysteine via cystathionine, providing cysteine for protein synthesis and for the synthesis of glutathione and other sulfur-containing compounds. This branch is a key node connecting methionine metabolism to redox defense. TFEB regulates sulfur amino acid and coenzyme A metabolism to support hepatic metabolic adaptation and redox homeostasis, underscoring the integration of transsulfuration with cellular stress responses.
Coenzyme A and downstream sulfur metabolites
In simple terms: Sulfur from amino acids is also used to build coenzyme A, a helper molecule in energy metabolism.
Sulfur amino acid metabolism feeds into coenzyme A biosynthesis, linking amino acid sulfur to central carbon and energy metabolism. This connection is part of the broader sulfurome, the collection of sulfur-containing metabolites measurable in plasma and urine. Dietary sulfur amino acid restriction produces a novel metabolic signature that correlates with loss of fat mass and adipose tissue gene expression, indicating that downstream sulfur metabolites have systemic effects.
Integrated stress response and serine synthesis
In simple terms: When sulfur amino acids are limited, cells activate a stress response and make more serine to cope.
Dietary sulfur amino acid restriction activates the integrated stress response, a signaling network that helps cells adapt to amino acid limitation. This response is mechanistically linked to improved glucose homeostasis through hepatic de novo serine synthesis. These findings show that sulfur amino acid metabolic process is not isolated but communicates with glucose and serine metabolism.
Posttranslational control of pathway enzymes
In simple terms: The enzymes in this pathway can be switched on or off by chemical modifications after they are made.
Mammalian sulfur amino acid metabolism is subject to posttranslational regulation, meaning that enzyme activity can be rapidly adjusted without changing gene expression. This layer of control allows the pathway to respond to nutritional and redox signals. Understanding these modifications is essential for interpreting CRISPR perturbation experiments.
Key Genes Involved in GO:0000096 sulfur amino acid metabolic process
The following genes and proteins are central to sulfur amino acid metabolic process and are frequently studied in metabolic, oncological, and nutritional research.
| Gene | Major Role | Research Relevance |
|---|---|---|
| MTR | Methionine synthase; remethylates homocysteine to methionine | Target for studying methionine recycling and one-carbon metabolism |
| MTHFR | Methylenetetrahydrofolate reductase; supports methionine synthesis | Relevant to folate and sulfur amino acid interconnections |
| CBS | Cystathionine beta-synthase; first step of transsulfuration | Key enzyme for cysteine synthesis and redox balance |
| CTH | Cystathionine gamma-lyase; second step of transsulfuration | Target for modulating cysteine and glutathione production |
| MAT1A | Methionine adenosyltransferase; produces S-adenosylmethionine | Central to methyl donation and hepatic sulfur metabolism |
| GNMT | Glycine N-methyltransferase; regulates SAM/SAH ratio | Involved in methionine flux and methylation capacity |
| AHCY | S-adenosylhomocysteine hydrolase; hydrolyzes SAH | Controls homocysteine levels and transmethylation flux |
| GCLC | Glutamate-cysteine ligase catalytic subunit; glutathione synthesis | Links cysteine availability to antioxidant defense |
| GCLM | Glutamate-cysteine ligase modifier subunit; glutathione synthesis | Modulates glutathione synthesis capacity |
| SLC7A11 | Cystine/glutamate antiporter; cystine uptake | Determines cysteine availability for sulfur metabolism |
| SLC1A5 | Glutamine transporter; supports amino acid exchange | Indirectly influences sulfur amino acid uptake |
| TFEB | Transcription factor; regulates sulfur amino acid and CoA metabolism | Master regulator of hepatic metabolic adaptation |
| ATF4 | Integrated stress response transcription factor | Mediates SAAR-induced stress response |
| PHGDH | Phosphoglycerate dehydrogenase; serine synthesis | Connects SAAR to glucose homeostasis |
| PSAT1 | Phosphoserine aminotransferase; serine synthesis | Part of the de novo serine pathway activated by SAAR |
| PSPH | Phosphoserine phosphatase; serine synthesis | Completes de novo serine synthesis linked to SAAR |
| MARS | Methionyl-tRNA synthetase; charges methionine onto tRNA | Essential for protein synthesis using sulfur amino acids |
| CARS | Cysteinyl-tRNA synthetase; charges cysteine onto tRNA | Essential for cysteine incorporation into proteins |
How Is sulfur amino acid metabolic process Regulated?
Sulfur amino acid metabolic process is regulated at multiple levels. TFEB regulates sulfur amino acid and coenzyme A metabolism to support hepatic metabolic adaptation and redox homeostasis, linking transcriptional control to nutrient status. Posttranslational regulation of mammalian sulfur amino acid metabolism provides rapid, reversible control of enzyme activity. Dietary sulfur amino acid restriction activates the integrated stress response, which reprograms gene expression to cope with amino acid limitation. In addition, SAAR improves glucose homeostasis through hepatic de novo serine synthesis, indicating cross-talk between sulfur amino acid and glucose metabolic networks. These regulatory layers ensure that sulfur amino acid flux is matched to cellular demand for methylation, redox balance, and protein synthesis.
sulfur amino acid metabolic process and Human Disease
| Gene | Disease / Biology | Potential Experimental Model |
|---|---|---|
| SLC7A11 | Leukemia; cystine uptake supports redox balance | CRISPR knockout in leukemia cell lines followed by viability assay |
| CBS | Hepatic redox homeostasis; transsulfuration | Knockout or point-mutation models in hepatocytes |
| TFEB | Hepatic metabolic adaptation and CoA metabolism | Overexpression and knockout in liver-derived cells |
| PHGDH | Glucose homeostasis via serine synthesis | Knockout in hepatocytes with SAAR treatment |
| ATF4 | Integrated stress response to SAAR | Knockout and reporter knock-in in metabolic cell models |
Leukemia and sulfur amino acid dependency
Obesity, adipose tissue, and metabolic syndrome
Hepatic metabolic adaptation and redox homeostasis
Parasitic protozoan infections
From sulfur amino acid metabolic process-Related Genes to Experimental Models
| Research Question | Suitable Model |
|---|---|
| Is a candidate sulfur amino acid enzyme required for cell proliferation? | |
| Does a specific point mutation alter enzyme activity in sulfur amino acid metabolism? | |
| Can a tagged version of a sulfur amino acid enzyme reveal its localization? | |
| Does overexpression of a sulfur amino acid transporter increase flux? | |
| Which genes mediate the integrated stress response to SAAR? | |
| Does TFEB regulate sulfur amino acid and CoA metabolism? |
How to Study the sulfur amino acid metabolic process Process
| Method | What It Measures | Typical Application |
|---|---|---|
| Metabolomics | Levels of sulfur-containing metabolites in plasma, urine, or cells | Sulfurome profiling after SAAR |
| RNA-seq | Gene expression changes in sulfur amino acid pathways | Adipose tissue and hepatic transcriptomics |
| CRISPR knockout screening | Genes required for growth under defined sulfur amino acid conditions | Leukemia and metabolic stress screens |
| Enzyme activity assay | Catalytic activity of sulfur amino acid enzymes | Posttranslational regulation studies |
| Western blot | Protein abundance and modification status | Validating knockout and overexpression models |
| Targeted metabolomics | Specific metabolites such as methionine, cysteine, and CoA | Pathway flux analysis |
| Reporter assays | Transcriptional activity of ATF4 or TFEB targets | Integrated stress response and TFEB regulation |
| Cell viability assay | Proliferation and survival under pathway perturbation | Leukemia and metabolic cell models |
Metabolomics and sulfurome profiling
Transcriptomics and gene expression analysis
CRISPR screening and functional genomics
Biochemical enzyme assays and posttranslational analysis
How CRISPR Can Be Used to Study GO:0000096 sulfur amino acid metabolic process
Knockout
Point Mutation
Knock-in
Overexpression
How EDITGENE Supports sulfur amino acid metabolic process Research
Researchers studying sulfur amino acid metabolic process-related genes often need to determine whether a candidate gene is causally involved in pathway flux, stress adaptation, or disease phenotypes. Rigorous causal inference requires well-controlled genetic models, from knockout to precise point mutations and tagged knock-ins, combined with functional readouts such as metabolomics and transcriptomics.
Contact EDITGENE today to design your custom CRISPR model for sulfur amino acid metabolic process research.
Frequently Asked Questions About sulfur amino acid metabolic process
What is GO:0000096 sulfur amino acid metabolic process?
GO:0000096 is the Gene Ontology biological process term for the chemical reactions and pathways involving amino acids containing sulfur, such as methionine and cysteine.
What genes are involved in sulfur amino acid metabolic process?
Key genes include MTR, MTHFR, CBS, CTH, MAT1A, GNMT, AHCY, GCLC, GCLM, SLC7A11, TFEB, ATF4, PHGDH, PSAT1, and PSPH.
Why is sulfur amino acid metabolism important?
It supports protein synthesis, one-carbon metabolism, redox homeostasis, and coenzyme A production, and is linked to obesity, leukemia, and hepatic metabolic adaptation.
How does dietary sulfur amino acid restriction affect humans?
SAAR alters the plasma and urine sulfurome and produces a metabolic signature that correlates with loss of fat mass and adipose tissue gene expression in humans with overweight and obesity.
What is the integrated stress response in sulfur amino acid restriction?
Dietary sulfur amino acid restriction activates the integrated stress response, a signaling network that helps cells adapt to amino acid limitation.
How is sulfur amino acid metabolism regulated?
It is regulated by TFEB, by posttranslational modifications of pathway enzymes, and by the integrated stress response.
Is sulfur amino acid metabolism a cancer target?
Targeting the sulfur-containing amino acid pathway is being explored in leukemia, and SLC7A11 is a key gene in this context.
What methods are used to study sulfur amino acid metabolic process?
Metabolomics, RNA-seq, CRISPR screening, enzyme activity assays, and reporter assays are commonly used.
How does SAAR improve glucose homeostasis?
SAAR improves glucose homeostasis through hepatic de novo serine synthesis involving PHGDH, PSAT1, and PSPH.
What CRISPR models are available for sulfur amino acid research?
Knockout, point-mutation, knock-in, tagged knock-in, and overexpression models can be generated for genes in this pathway.
Conclusion
GO:0000096 sulfur amino acid metabolic process is a fundamental biological process that connects dietary sulfur amino acid intake to redox homeostasis, one-carbon metabolism, coenzyme A synthesis, and glucose homeostasis. Its dysregulation is implicated in leukemia and metabolic disease, and it is regulated by TFEB, the integrated stress response, and posttranslational modifications. CRISPR-based models, combined with metabolomics and transcriptomics, provide powerful tools to dissect causal mechanisms and identify therapeutic opportunities.
References
- 1. Olsen T et al.. 2024. Dietary sulfur amino acid restriction in humans with overweight and obesity: Evidence of an altered plasma and urine sulfurome, and a novel metabolic signature that correlates with loss of fat mass and adipose tissue gene expression.. Redox Biol 73:103192 PMID: 38776754
- 2. Chen X et al.. 2024. Targeting the sulfur-containing amino acid pathway in leukemia.. Amino Acids 56(1):47 PMID: 39060524
- 3. Matye D et al.. 2022. TFEB regulates sulfur amino acid and coenzyme A metabolism to support hepatic metabolic adaptation and redox homeostasis.. Nat Commun 13(1):5696 PMID: 36171419
- 4. Pajares MÁ. 2025. Posttranslational Regulation of Mammalian Sulfur Amino Acid Metabolism.. Int J Mol Sci 26(6) PMID: 40141131
- 5. Courtney-Martin G et al.. 2012. Sulfur amino acid metabolism and requirements.. Nutr Rev 70(3):170-5 PMID: 22364159
- 6. Ortega AF et al.. 2026. Dietary sulfur amino acid restriction improves glucose homeostasis through hepatic de novo serine synthesis.. Mol Metab 105:102325 PMID: 41644011
- 7. Nozaki T et al.. 2005. Sulfur-containing amino acid metabolism in parasitic protozoa.. Adv Parasitol 60:1-99 PMID: 16230102
- 8. Jonsson WO et al.. 2019. Dietary Sulfur Amino Acid Restriction and the Integrated Stress Response: Mechanistic Insights.. Nutrients 11(6) PMID: 31208042
