ABOVE: MODIFIED FROM
© MOLLY THOMPSON
Gut bacteria harbor enzymes and pump out other molecules that can influence how medications are activated or broken down. One example is the Parkinson’s drug levodopa (L-dopa), for which studies have suggested these interactions help explain differences in efficacy among individuals.
Researchers found that some gut bacteria produce an enzyme called tyrosine decarboxylase that can convert L-dopa into dopamine as the drug passes through the small intestine, before it can reach the brain. Testing the stool of patients with Parkinson’s, the team discovered that the abundance of the bacterial gene for tyrosine decarboxylase correlated with a need for a higher dose of L-dopa to control their symptoms (Nat Commun, 10:310, 2019). Another team identified a small-molecule inhibitor that appears to block the enzyme’s action in mice (Science, 364:eaau6323, 2019).
After crossing the blood-brain barrier, L-dopa is converted to dopamine by neurons’ own enzymes to ...
