Chorismate

evidence_access

Primary indexed abstract reviewed; full results, tables and supplements not independently extracted.

experimental_model

Escherichia coli biochemical pathway; source-specific enzyme evidence recorded in the passage.

interpretation_status

Source-derived extraction of a fact-checked reference; access is explicit, not independent raw-data verification.

limitations

Interpret only within the recorded preparation, exposure and comparator. The complete source passage retains qualifications; unspecified doses/timing have not been extracted here. No clinical efficacy, nutrient deficiency or unique molecular mediation is inferred.

plain_language

PabB forms aminodeoxychorismate using nitrogen supplied by the glutamine/PabA system.

primary_references

Characterization and sequence of Escherichia coli pabC, the gene encoding aminodeoxychorismate lyase, a pyridoxal phosphate-containing enzyme. | 1992 | DOI 10.1128/jb.174.16.5317-5323.1992 | PMID 1644759 | https://pubmed.ncbi.nlm.nih.gov/1644759/ | https://doi.org/10.1128/jb.174.16.5317-5323.1992 | https://pmc.ncbi.nlm.nih.gov/articles/PMC206368/

primary_references

para-aminobenzoate synthesis from chorismate occurs in two steps. | 1989 | DOI 10.1016/s0021-9258(18)81833-6 | PMID 2656685 | https://pubmed.ncbi.nlm.nih.gov/2656685/ | https://doi.org/10.1016/s0021-9258(18)81833-6

source_locator

Reviewed reference lines 25-25; exact primary location described in quoted passage where extracted.

Shikimic acid: detailed mechanisms of action (reviewed 5 October 2026) · lines 25–25

Original AI-assisted review of primary studies and, where relevant, official regulatory records. Access level is retained per claim. Corrections, null results and unresolved questions remain explicit. Not publisher full text or independent replication. · supports · Escherichia coli biochemical pathway; source-specific enzyme evidence recorded in the passage. · source_derived_draft · unverified_draft

**The folate branch contains a B6-dependent step.** In E. coli, PabA supplies nitrogen from glutamine, generating glutamate; PabB uses chorismate and that nitrogen to form 4-amino-4-deoxychorismate. PabC then cleaves this intermediate to p-aminobenzoate (pABA) and pyruvate. The purified PabC enzyme contains pyridoxal phosphate (PLP), a B6 cofactor. A disrupted pabC strain required external pABA for growth. This establishes a microbial cofactor and biosynthetic dependency, not that marginal human B6 deficiency causes microbial folate failure. pABA is a precursor used in bacterial folate synthesis, not folate itself. [para-aminobenzoate synthesis from chorismate occurs in two steps.](https://pubmed.ncbi.nlm.nih.gov/2656685/) [Characterization and sequence of Escherichia coli pabC, the gene encoding aminodeoxychorismate lyase, a pyridoxal phosphate-containing enzyme.](https://pubmed.ncbi.nlm.nih.gov/1644759/)

evidence_access

Primary full text retrieved; relevant methods/results/figures reviewed. Selective extraction, not raw-data reanalysis or exhaustive supplemental extraction.

experimental_model

E. coli pathway map/engineering context.

interpretation_status

Source-derived extraction of a fact-checked reference; access is explicit, not independent raw-data verification.

limitations

Multistep precursor relationship; not one reaction, direct conversion by humans, or measured host nutrient delivery.

plain_language

Chorismate supplies a multistep E. coli biosynthetic branch toward l-phenylalanine.

primary_references

Metabolic engineering of Escherichia coli for shikimate pathway derivative production from glucose-xylose co-substrate. | 2020 | DOI 10.1038/s41467-019-14024-1 | PMID 31937786 | https://pubmed.ncbi.nlm.nih.gov/31937786/ | https://doi.org/10.1038/s41467-019-14024-1 | https://pmc.ncbi.nlm.nih.gov/articles/PMC6959354/

source_locator

Reviewed reference lines 23-23; exact primary location described in quoted passage where extracted.

Shikimic acid: detailed mechanisms of action (reviewed 5 October 2026) · lines 23–23

Original AI-assisted review of primary studies and, where relevant, official regulatory records. Access level is retained per claim. Corrections, null results and unresolved questions remain explicit. Not publisher full text or independent replication. · supports · E. coli pathway map/engineering context. · source_derived_draft · unverified_draft

**Aromatic amino acids and competing branches.** Chorismate feeds organism-dependent synthesis of phenylalanine, tyrosine and tryptophan. The E. coli engineering study shows that central carbon supply and competing reactions can redistribute product yields; it does not measure host nutrient delivery. Humans obtain essential phenylalanine and tryptophan through nutrition and can convert phenylalanine to tyrosine through a different pathway. Bacterial synthesis, extracellular release, community use and human absorption are separate stages. Chorismate also participates in specialized siderophore pathways in some organisms, but no universal increase in iron delivery follows from having more precursor. [Metabolic engineering of Escherichia coli for shikimate pathway derivative production from glucose-xylose co-substrate.](https://pubmed.ncbi.nlm.nih.gov/31937786/)

evidence_access

Primary full text retrieved; relevant methods/results/figures reviewed. Selective extraction, not raw-data reanalysis or exhaustive supplemental extraction.

experimental_model

E. coli pathway map/engineering context.

interpretation_status

Source-derived extraction of a fact-checked reference; access is explicit, not independent raw-data verification.

limitations

Multistep precursor relationship; not one reaction, direct conversion by humans, or measured host nutrient delivery.

plain_language

Chorismate supplies a multistep E. coli biosynthetic branch toward l-tryptophan.

primary_references

Metabolic engineering of Escherichia coli for shikimate pathway derivative production from glucose-xylose co-substrate. | 2020 | DOI 10.1038/s41467-019-14024-1 | PMID 31937786 | https://pubmed.ncbi.nlm.nih.gov/31937786/ | https://doi.org/10.1038/s41467-019-14024-1 | https://pmc.ncbi.nlm.nih.gov/articles/PMC6959354/

source_locator

Reviewed reference lines 23-23; exact primary location described in quoted passage where extracted.

Shikimic acid: detailed mechanisms of action (reviewed 5 October 2026) · lines 23–23

Original AI-assisted review of primary studies and, where relevant, official regulatory records. Access level is retained per claim. Corrections, null results and unresolved questions remain explicit. Not publisher full text or independent replication. · supports · E. coli pathway map/engineering context. · source_derived_draft · unverified_draft

**Aromatic amino acids and competing branches.** Chorismate feeds organism-dependent synthesis of phenylalanine, tyrosine and tryptophan. The E. coli engineering study shows that central carbon supply and competing reactions can redistribute product yields; it does not measure host nutrient delivery. Humans obtain essential phenylalanine and tryptophan through nutrition and can convert phenylalanine to tyrosine through a different pathway. Bacterial synthesis, extracellular release, community use and human absorption are separate stages. Chorismate also participates in specialized siderophore pathways in some organisms, but no universal increase in iron delivery follows from having more precursor. [Metabolic engineering of Escherichia coli for shikimate pathway derivative production from glucose-xylose co-substrate.](https://pubmed.ncbi.nlm.nih.gov/31937786/)

evidence_access

Primary full text retrieved; relevant methods/results/figures reviewed. Selective extraction, not raw-data reanalysis or exhaustive supplemental extraction.

experimental_model

E. coli pathway map/engineering context.

interpretation_status

Source-derived extraction of a fact-checked reference; access is explicit, not independent raw-data verification.

limitations

Multistep precursor relationship; not one reaction, direct conversion by humans, or measured host nutrient delivery.

plain_language

Chorismate supplies a multistep E. coli biosynthetic branch toward l-tyrosine.

primary_references

Metabolic engineering of Escherichia coli for shikimate pathway derivative production from glucose-xylose co-substrate. | 2020 | DOI 10.1038/s41467-019-14024-1 | PMID 31937786 | https://pubmed.ncbi.nlm.nih.gov/31937786/ | https://doi.org/10.1038/s41467-019-14024-1 | https://pmc.ncbi.nlm.nih.gov/articles/PMC6959354/

source_locator

Reviewed reference lines 23-23; exact primary location described in quoted passage where extracted.

Shikimic acid: detailed mechanisms of action (reviewed 5 October 2026) · lines 23–23

Original AI-assisted review of primary studies and, where relevant, official regulatory records. Access level is retained per claim. Corrections, null results and unresolved questions remain explicit. Not publisher full text or independent replication. · supports · E. coli pathway map/engineering context. · source_derived_draft · unverified_draft

**Aromatic amino acids and competing branches.** Chorismate feeds organism-dependent synthesis of phenylalanine, tyrosine and tryptophan. The E. coli engineering study shows that central carbon supply and competing reactions can redistribute product yields; it does not measure host nutrient delivery. Humans obtain essential phenylalanine and tryptophan through nutrition and can convert phenylalanine to tyrosine through a different pathway. Bacterial synthesis, extracellular release, community use and human absorption are separate stages. Chorismate also participates in specialized siderophore pathways in some organisms, but no universal increase in iron delivery follows from having more precursor. [Metabolic engineering of Escherichia coli for shikimate pathway derivative production from glucose-xylose co-substrate.](https://pubmed.ncbi.nlm.nih.gov/31937786/)

evidence_access

Primary indexed abstract reviewed; full results, tables and supplements not independently extracted.

experimental_model

Escherichia coli biochemical pathway; source-specific enzyme evidence recorded in the passage.

interpretation_status

Source-derived extraction of a fact-checked reference; access is explicit, not independent raw-data verification.

limitations

Interpret only within the recorded preparation, exposure and comparator. The complete source passage retains qualifications; unspecified doses/timing have not been extracted here. No clinical efficacy, nutrient deficiency or unique molecular mediation is inferred.

plain_language

E. coli UbiC converts chorismate toward the 4-hydroxybenzoate precursor of bacterial ubiquinone.

primary_references

Biosynthesis of ubiquinone in Escherichia coli K-12: biochemical and genetic characterization of a mutant unable to convert chorismate into 4-hydroxybenzoate. | 1974 | DOI 10.1128/jb.118.1.41-45.1974 | PMID 4595202 | https://pubmed.ncbi.nlm.nih.gov/4595202/ | https://doi.org/10.1128/jb.118.1.41-45.1974 | https://pmc.ncbi.nlm.nih.gov/articles/PMC246637/

primary_references

The role of shikimic acid in the biosynthesis of vitamin K2. | 1966 | DOI 10.1042/bj1000001 | PMID 5337721 | https://pubmed.ncbi.nlm.nih.gov/5337721/ | https://doi.org/10.1042/bj1000001 | https://pmc.ncbi.nlm.nih.gov/articles/PMC1265084/

source_locator

Reviewed reference lines 27-27; exact primary location described in quoted passage where extracted.

Shikimic acid: detailed mechanisms of action (reviewed 5 October 2026) · lines 27–27

Original AI-assisted review of primary studies and, where relevant, official regulatory records. Access level is retained per claim. Corrections, null results and unresolved questions remain explicit. Not publisher full text or independent replication. · supports · Escherichia coli biochemical pathway; source-specific enzyme evidence recorded in the passage. · source_derived_draft · unverified_draft

**The K and Q branches are organism-specific.** Isotope experiments in E. coli traced shikimate carbon into the benzene ring of menaquinone-8 (MK-8), and methionine-derived methyl carbon into that product. This does not establish increased human MK-7, vitamin-K function or an oral shikimate dose response. Separately, an E. coli ubiC mutant failed to convert chorismate to 4-hydroxybenzoate and produced little ubiquinone unless supplied with 4-hydroxybenzoate. UbiC therefore identifies a branch-specific supply bottleneck; bacterial ubiquinone production is not synonymous with human mitochondrial CoQ10 synthesis. [The role of shikimic acid in the biosynthesis of vitamin K2.](https://pubmed.ncbi.nlm.nih.gov/5337721/) [Biosynthesis of ubiquinone in Escherichia coli K-12: biochemical and genetic characterization of a mutant unable to convert chorismate into 4-hydroxybenzoate.](https://pubmed.ncbi.nlm.nih.gov/4595202/)

evidence_access

Primary indexed abstract reviewed; full results, tables and supplements not independently extracted.

experimental_model

Escherichia coli biochemical pathway; source-specific enzyme evidence recorded in the passage.

interpretation_status

Source-derived extraction of a fact-checked reference; access is explicit, not independent raw-data verification.

limitations

Interpret only within the recorded preparation, exposure and comparator. The complete source passage retains qualifications; unspecified doses/timing have not been extracted here. No clinical efficacy, nutrient deficiency or unique molecular mediation is inferred.

plain_language

AroC forms chorismate from EPSP with reduced-FMN dependence and phosphate elimination.

primary_references

Evidence for a major structural change in Escherichia coli chorismate synthase induced by flavin and substrate binding. | 1998 | DOI 10.1042/bj3350319 | PMID 9761730 | https://pubmed.ncbi.nlm.nih.gov/9761730/ | https://doi.org/10.1042/bj3350319 | https://pmc.ncbi.nlm.nih.gov/articles/PMC1219785/

primary_references

Mechanism of chorismate synthase. Role of the two invariant histidine residues in the active site. | 2004 | DOI 10.1074/jbc.m312471200 | PMID 14668332 | https://pubmed.ncbi.nlm.nih.gov/14668332/ | https://doi.org/10.1074/jbc.m312471200

source_locator

Reviewed reference lines 21-21; exact primary location described in quoted passage where extracted.

Shikimic acid: detailed mechanisms of action (reviewed 5 October 2026) · lines 21–21

Original AI-assisted review of primary studies and, where relevant, official regulatory records. Access level is retained per claim. Corrections, null results and unresolved questions remain explicit. Not publisher full text or independent replication. · supports · Escherichia coli biochemical pathway; source-specific enzyme evidence recorded in the passage. · source_derived_draft · unverified_draft

**Chorismate synthase needs reduced FMN.** E. coli AroC converts EPSP to chorismate with phosphate elimination. Reduced FMN is required although the overall substrate conversion is not a net redox reaction; flavin is a catalytic cofactor rather than a stoichiometrically consumed vitamin. The 1998 study observed a stable oxidized-FMN/EPSP/enzyme complex without productive turnover. Binding, cofactor quantity and cofactor redox state therefore answer different questions. In Neurospora crassa, bifunctional chorismate synthase can use NADPH to reduce its flavin; that reductase capability must not be assigned to every bacterial AroC. [Evidence for a major structural change in Escherichia coli chorismate synthase induced by flavin and substrate binding.](https://pubmed.ncbi.nlm.nih.gov/9761730/) [Mechanism of chorismate synthase. Role of the two invariant histidine residues in the active site.](https://pubmed.ncbi.nlm.nih.gov/14668332/)