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. 2025 Nov 26;17(1):2589493. doi: 10.1080/19490976.2025.2589493

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© 2025 The Author(s). Published with license by Taylor & Francis Group, LLC.

This is an Open Access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/4.0/), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. The terms on which this article has been published allow the posting of the Accepted Manuscript in a repository by the author(s) or with their consent.

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Figure 2. — Transformation pathway of phytosterols. (i) 2,3-Oxidosqualene is synthesized from acetyl-CoA through a series of enzymatic reactions and subsequently converted into cycloartenol using cycloartenol as a key metabolic node; (ii) one branch of the metabolic flux toward the cholesterol biosynthesis pathway; and (iii) another branch is directed toward the 4-methyl-24-methylenelophenol, which serves as a precursor for (1) the formation of β-sitosterol and stigmasterol, (2) the biosynthesis of campesterol, and (3) the biosynthesis of brassicasterol. Abbreviations: 1. HMGR, 3-hydroxy-3-methylglutaryl-CoA reductase; 2. GPPS, geranyl diphosphatesynthase; 3. FPPS, farnesyl diphosphate synthase; 4. SQS, squalene synthase; 5. SQE, squalene epoxidase; 6. CAS, cycloartenol synthase; 7. SMT1, sterol C24-methyltransferase 1; 8. SMO1, sterol-4α-methyl oxidase 1; 9. CPI, cyclopropyl sterol isomerase; 10. CYP51, sterol C14-demethylase; 11. C14-R, sterol C14 reductase; 12. 8,7-SI, sterol δ8-δ7 isomerase; 13. SMT2, sterol C24-methyltransferase 2; 14. SMO2, sterol-4α-methyl oxidase 2; 15. SC5D, sterol C5-desaturase; 16. 7-DR1, sterol δ7-reductase; 17. SSR1, sterol side chain reductase 1; 18. SC22D, sterol C22-desaturase; 19. ERG4, C24(28) sterol reductase; 20. SC4DM, sterol C-4 demethylation complex enzymes; 21. LBR, δ(14)-sterol reductase; 22. EBP, C-8 sterol isomerase; 23. SC5DL, sterol-C5-desaturase; 24. DHCR7, 7-dehydrocholesterol reductase; HMG-CoA, 3-hydroxy-3-methylglutaryl coenzyme A; IPP, isopentenyl pyrophosphate; DMAPP, dimethylallyl pyrophosphate; GPP, geranyl diphosphate; FPP: farnesyl pyrophosphate.