--- title: "Rubisco carboxylation Template – Chemistry Diagram | MolDraw" url: https://www.moldraw.com/templates/enzyme-rubisco-carboxylation/ description: "Rubisco carboxylation template: In the Mg²⁺–carbamylated-Lys201 active site of rubisco the carbamate removes the C3 proton of ribulose 1,5-bisphosphate to…" lang: en publisher: Scidart Academy generated: 2026-11-13 --- [MolDraw](https://www.moldraw.com/) › [Templates](https://www.moldraw.com/templates/) › [Biochemistry](https://www.moldraw.com/templates/biochemistry/) › Rubisco carboxylation [Biochemistry](https://www.moldraw.com/templates/biochemistry/)Premium # Rubisco carboxylation template ![Rubisco carboxylation template: In the Mg²⁺–carbamylated-Lys201 active site of rubisco the carbamate removes the C3 proton of ribulose 1,5-bisphosphate to give the 2,3-enediolate, which adds CO₂ at C2 to give 2′-carboxy-3-keto-arabinitol 1,5-bisphosphate; hydration at C3 and C2–C3 cleavage give one 3-phosphoglycerate and a C2 carbanion that is protonated to the second.](https://www.moldraw.com/templates/enzyme-rubisco-carboxylation.webp) [Edit in MolDraw](https://www.moldraw.com/)Download with Pro Premium template. Preview and edit it free in MolDraw; downloading and exporting it is part of [MolDraw Pro](https://www.moldraw.com/pricing). In the Mg²⁺–carbamylated-Lys201 active site of rubisco the carbamate removes the C3 proton of ribulose 1,5-bisphosphate to give the 2,3-enediolate, which adds CO₂ at C2 to give 2′-carboxy-3-keto-arabinitol 1,5-bisphosphate; hydration at C3 and C2–C3 cleavage give one 3-phosphoglycerate and a C2 carbanion that is protonated to the second. ## Mechanism step by step The RuBP 2,3-enediolate adds CO₂ at C2; the β-keto acid is hydrated and cleaved to two 3-phosphoglycerates 1. **Enolisation** – The Lys201 carbamate (on Mg²⁺) removes the C3 proton: the 2,3-enediolate 2. **Proton shift** – The O3 proton moves to O2 (both oxygens are on Mg²⁺) 3. **Carboxylation** – C2 of the enediolate adds to CO₂: the β-keto acid 4. **Hydration** – Mg²⁺-bound OH⁻ adds to the C3 ketone: a gem-diolate 5. **C2–C3 cleavage** – C3 becomes a carboxylate (upper 3-PG); C2 keeps the electrons as a carbanion 6. **Protonation** – Lys175–H⁺ protonates C2 on one face: the second D-3-phosphoglycerate ## Key points - Rubisco is active only after CO₂ (not the substrate CO₂) carbamylates Lys201 and Mg²⁺ binds the carbamate; rubisco activase helps release inhibitory sugar phosphates. - The upper 3-PG (C3–C5 of RuBP) leaves as the carboxylate from hydration; the lower one carries C1, C2 and the new CO₂ carbon. - O₂ competes with CO₂ for the same enediolate: oxygenation gives 3-PG + 2-phosphoglycolate (photorespiration). - Rubisco is slow (kcat ≈ 3 s⁻¹) and may be the most abundant protein on Earth; it fixes CO₂ in the Calvin cycle in the chloroplast stroma. Drawn with 165 atoms, 21 arrows, 9 shapes – every one editable in MolDraw. ## Sources - [Nelson & Cox, Lehninger Principles of Biochemistry, 8th ed., 2021, ch. 20](https://openlibrary.org/isbn/9781319228002) Textbook - [Berg, Tymoczko, Gatto & Stryer, Biochemistry, 9th ed., 2019, ch. 20](https://openlibrary.org/isbn/9781319114657) Textbook - [Cleland, Andrews, Gutteridge, Hartman & Lorimer, Chem. Rev. 1998, 98, 549](https://doi.org/10.1021/cr970010r) Review ## How to use this template 1. Press **Edit in MolDraw**. The template opens on the canvas of the free MolDraw editor. 2. Change anything: move structures, edit atoms and labels, recolour highlights or delete what you do not need. 3. Add your own structures, arrows and text next to it, or combine several templates on one page. 4. Export the drawing as PNG, SVG or PDF for slides, worksheets, theses and papers. ## Frequently asked questions ### Is the Rubisco carboxylation template free? You can preview the Rubisco carboxylation template here and open and edit it in MolDraw for free. Downloading or exporting it is part of MolDraw Pro, together with the other premium templates. ### Can I edit the Rubisco carboxylation template? Yes. It opens as an ordinary MolDraw drawing, so every structure, arrow, label and colour can be changed, and you can add your own content around it. ### Is the chemistry checked? Every structure is checked with RDKit and every curly arrow passes MolDraw’s electron-flow audit. The sources used are listed on this page. ### Are the biochemical pathways drawn with structures? Yes. 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