Likely none. The paper describes finding an enzyme that can cleave catecholamine precursors. OK? There's literally only one catecholamine precursor that's used

Likely none. The paper describes finding an enzyme that can cleave catecholamine precursors. OK? There's literally only one catecholamine precursor that's used medically, and that's L-DOPA. We know Parkinson's medications work, and very effectively. L-DOPA is used effectively, despite being metabolized by gut flora.