For over 30 years, levodopa, the chemical precursor of dopamine, has been the primary medication for PD patients.

FORBES: Putting A Patch On Parkinson's Disease

Codexis's technology works with pharmaceutical precision indeed, one of its main commercial products is the enzyme system for making the chemical precursor to Lipitor, a cholesterol-lowering drug that is marketed by Pfizer.

ECONOMIST: Advanced biofuels

L-dopa, a chemical precursor to dopamine.

ECONOMIST: The Nobel prizes

In 2011, the US director of national intelligence concluded that Syria remained "dependent on foreign sources for key elements" of its chemical weapons programme, including precursor chemicals, which are generally dual-use chemicals that can be combined to produce blister or nerve agents.

BBC: Syria's chemical weapons stockpile