An efficient and stable ascorbate/O2-driven route for L-DOPA synthesis by heme-dependent tyrosine hydroxylase

Liao, L.; Bao, Z.; Jiang, Z.; Li, A.; wang, b.

doi:10.64898/2026.04.24.720734

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bioRxiv · 10.64898/2026.04.24.720734

An efficient and stable ascorbate/O2-driven route for L-DOPA synthesis by heme-dependent tyrosine hydroxylase

Liao, L.·Bao, Z.·Jiang, Z.·Li, A.·wang, b.

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Abstract

L-DOPA is a key therapeutic agent for Parkinsons disease, with growing demand due to global population aging. Here we report that heme-dependent tyrosine hydroxylase (TyrH) can utilize an ascorbate/O2 system--as an alternative to H2O2--to synthesize L-DOPA with markedly enhanced operational stability. While exogenous H2O2 rapidly inactivates TyrH within minutes, sodium ascorbate (NaAsc) enables sustained catalysis for up to 24 h, surpassing the H2O2-driven yield after only 30 min. UV-vis spectroscopy confirms that H2O2 readily degrades the heme center, whereas the heme remains intact in the presence of NaAsc. QM/MM simulations reveal that in situ generated H2O2 leads to the active species of Compound I for tyrosine hydroxylation. Through systematic optimization, we establish efficient reaction conditions (40 {micro}M TyrH, 1 mM L-Tyr, 100 mM NaAsc, pH 8.5, 40 {degrees}C), achieving >95% conversion of L-Tyr to L-DOPA within 2 h. This work not only provides a robust and sustainable biocatalytic route for L-DOPA production but also highlights the broader applicability of the ascorbate/O2 pathway in heme-enzyme catalysis.

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Liao, L., Bao, Z., Jiang, Z., Li, A., wang, b.. 2026-04-28. An efficient and stable ascorbate/O2-driven route for L-DOPA synthesis by heme-dependent tyrosine hydroxylase. https://doi.org/10.64898/2026.04.24.720734

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