You'd think in micro/molecular bio, we'd be interested in L-cysteine as an amino acid (and we are, when we think of disulfide bridges).
You'd probably be suprised that on a day-to-day basis, we generally think of it as 'that reducing agent we add to anaerobic media to scrub out trace oxygen'. Unsurprisingly, a common amino acid tends to be rather non-toxic to the bugs we want to grow.
I didn't know that people are actually using cysteine to remove trace oxygen ?!
Well, lots of broth are just some peptides and amino acids, so cysteine should be there and should be non toxic (but also help bugs grow too ?!!) Haha XDDIs it really a general protocol? I thought it is just commonly used for scavenging ROS in cell.
Oh, absolutely. It's fairly common since it's so gentle and non-toxic.
The biggest problem is that it's also slow. We usually add resazuring as a redox indicator at the same time, prior to inoculation. We have to wait for it to go from pink to clear, and this can take a few hours at 37 C, even if we prepare using water boiled under N2/CO2 and keep an anoxic headspace and it's just scavenging the last traces of oxygen.
Forgot to add, we generally schedule anaerobic media prep around dinner/pub time for that reason.