Peroxygenase-Catalyzed Selective Synthesis of Calcitriol Starting from Alfacalcidol

Abstract

Calcitriol is an active analog of vitamin D3 and has excellent physiological activities in regulating healthy immune function. To synthesize the calcitriol compound, the concept of total synthesis is often adopted, which typically involves multiple steps and results in an overall low yield. Herein, we envisioned an enzymatic approach for the synthesis of calcitriol. Peroxygenase from Agrocybe aegerita (AaeUPO) was used as a catalyst to hydroxylate the C-H bond at the C-25 position of alfacalcidol and yielded the calcitriol in a single step. The enzymatic reaction yielded 80.3% product formation in excellent selectivity, with a turnover number up to 4000. In a semi-preparative scale synthesis, 72% isolated yield was obtained. It was also found that AaeUPO is capable of hydroxylating the C-H bond at the C-1 position of vitamin D3, thereby enabling the calcitriol synthesis directly from vitamin D3.

Characterization of Pt/g-C3N4-Catalyzed Methanol Oxidation to Drive Peroxygenase-Catalyzed Oxyfunctionalization of Hydrocarbons

“…Recombinant unspecific peroxygenase from A. aegerita (r Aae UPO) was produced and purified according to previously described procedures …”

“…Recombinant unspecific peroxygenase from A. aegerita (rAaeUPO) was produced and purified according to previously described procedures. 47 Photobiocatalytic Hydroxylation of Ethylbenzene. To a 4 mL transparent glass vial, 2 mg of the photocatalyst was added into 1.9 mL of phosphate buffer (pH 7.0), then 100 nM rAaeUPO, 40 mM ethylbenzene, and 150 mM methanol were added, and the volume of the suspension was adjusted to 2 mL.…”

Structural diversification of vitamin D using microbial biotransformations

“…These synthetic analogs often incorporate modifications to the side chain or the A-ring of the molecule, which can enhance their activity or target specific pathways. For example, alfacalcidol is a prodrug that is converted in vivo to calcitriol, circumventing the need for renal hydroxylation, which can be beneficial in patients with renal impairment (Li et al 2022 ). Several strategies can be used to enhance the stability of vitamin D APIs during synthesis and storage.…”