Sequential detection of dopamine and L-DOPA by a 2,3-dopa- dioxygenase from Streptomyces sclerotialus

A variety of enzyme-based colorimetric biosensors have been developed for clinical practice; however, these methods will only become cost-effective when they are able to process multiple samples with a high degree of sensitivity. In this study, a novel heat-stable enzyme, 2,3-dopa-dioxygenase from the thermophilic bacterium Streptomyces sclerotialus (SsDDO), was used in the development of a protein-and cell-based biosensor for the detection of L-DOPA for the first time. SsDDO catalyzes the oxidative cleavage of L-DOPA forms linear semialdehyde (AHMS) and cyclizes to a 3-carboxy-3-hydroxyallylidene3,4-dihydropyrrole-2-carboxylic acid (CHAPCA). We next derivatized CHAPCA by reacting with 3aminobenzoic acid (MABA) to yield a red-fluorescent pigment. Overall, the detection of L-DOPA via the red fluorescent signal can be completed in only 30 min. We also developed a sequential analysis method to detect the coexistence of dopamine and L-DOPA with a high degree of sensitivity using the dual-fluorescent signals to monitor the therapy of patients with Parkinson's disease treated with L-DOPA. The robustness and applicability of the system were further validated in serum. In addition, paper microfluidics modified with chitosan was applied for fast and cost-effective analysis of dopamine and LDOPA in the mixed solutions.(c) 2022 Elsevier B.V. All rights reserved.

Automated summary

A novel heat-stable enzyme was developed for a protein-and cell-based biosensor, enabling the detection of L-DOPA for the first time. The detection of L-DOPA was achieved through a red fluorescent signal within 30 minutes. Furthermore, a sequential analysis method using dual-fluorescent signals was developed for the sensitive detection of dopamine and L-DOPA coexistence, allowing for monitoring of the therapy for Parkinson's disease patients treated with L-DOPA.