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9:13nitrogen, and then you have an amino group on the other end, but then that's also connected to a caroxile group, which is the CO, carbon, oxygen, oxygen, hydrogen. Okay? So, it's not symmetric. M >> there's going to be a process called decarbon decarboxilation where you take that caroxile group out and now it becomes a symmetric molecule right there's an amino group H2N on one end and then there's an NH2 on the other end the the switching of the letters is just to show that it's completely symmetric >> if I were to look at this molecule cadaavverine this way and then I were to switch it around it would look the same to me >> okay >> okay now if that is an intermediate then what should happen. Another enzyme
9:54would take that intermediate and then it could grab on one end or it could grab the other end. Right. >> Right. Because it doesn't know >> which way came out of the enzyme. Right. Which one which part which end of the molecule the left or right had this CO attached. It doesn't know because it's just freely floating around. So this next step enzyme is going to grab that. >> And if I were to do radioisotope tagging Yes. of this molecule and I were to make a ring out of it with the nitrogen on one end and let's say that nitrogen is our index of reference. The radioarbon could be either on the left or the right, right? Because >> the whatever molecule turned it into a ring grabbed that cadaavverine from
10:35either the left end or the right end. Okay? And that's what we see in a lot of our um stepwise symmetric pathways. These are called stepwise symmetric. Okay? in the sense that it doesn't know which one it grabbed. And so that top line, you get a nitrogen um you get this heterocarbon ring with the nitrogen and that tagged carbon is either to the left of the nitrogen >> or to the right of the nitrogen. >> Now that happens in some plants, but in other plants that tagged carbon is always going to be on the left of the nitrogen. >> Interesting. Okay. >> Okay. So what is making it move from being a chance a 50/50 to 100% always
11:19being on a singular side which creates consistency. >> Exactly. And there's actually a lot of these compounds that are like this. Okay. From both lysine and ornithine you've got plants like nicotana flea. These guys make these asymmetric compounds. >> Sorry Nicotiana sounds like a Cardi B. >> It totally does. and she would be remiss to to say that you know it is an asymmetric um alkaloid you know but this is pretty common >> is the idea. >> Yep. Okay. Okay. >> So it's it's not a unique thing. We see it across a variety of these uh compounds. >> Yeah. Yeah. It's it's across a variety of these compounds. And so there's
12:00something very interesting going on. And this might seem kind of just like a boring trick. Okay. So you know your carbon is your tagged carbon is only on one side. >> But now let's think. Yeah. Who cares? But now let's actually before we even talk about like applications and stuff, let's actually think about okay what could be happening at the chemical level. >> Mhm. >> Such that my enzyme is always grabbing one end. >> Mhm. >> Right. Of a symmetric molecule. M it's it's a rod that looks exactly the same whether I were to do it this way or turn it around and yet the enzyme is always grabbing one end. And this is where we
12:41come to a hypothesis that was given in 1973 by Lener and Spencer in the Journal of American Chemical Society 1973. So this is 50 years ago. Mhm. >> They said the only way that this can happen is if there's a single process that goes from amino acid strips the CO and then makes the ring. If that intermediate cadaavverine were to go and freely float around, there's no way >> that the next enzyme would grab one end. This only happens if like you know in some analogy let's say I'm the enzyme with my right hand I grab the amino acid
13:22I strip the CO and then I put it to my left hand and I make a ring >> right I'm doing it in one smooth process there's not I'm grabbing it I'm letting it go and there's some other guy who's grabbing it because if the other guy grabs it it's had time to tumble >> in the 300 Kelvin environment of the cell right and so it's it's a very nice