Long before we invented plastics of our own, we had to make do with what nature provided. The most abundant organic compound by mass on earth is lignin, which is a bit of a nightmare. This is what makes up a good chunk of wood. I was taught that the evolutionary idea behind it was if the polymer is random and stable enough, enzymes will have a hard time evolving to eat it. This makes good sense. Trees have a hard time moving around and tend to stay put for long periods of time, so it serves them well to have mechanisms to prevent being eaten. Lacking teeth and all. Lignin is hard to make much use of, but we get better at it all the time.

The second most abundant organic compound by mass is cellulose. This is a bit more regular in structure. It is actually very close in structure to that of starch (your body’s own glucose polymer). The major difference is that one bond (the one in the upper right in the image below) points out of the plane of the screen instead of in (from this point of view). That means your enzymes can’t work on it. That’s why you can’t digest cotton (cellulose), paper (cellulose mostly, lignin’s not the best stuff for paper), etc.

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Here’s a quacky one for you. If you lived through the 70’s, you remember this as Laetrile. Amygdalin is a cyanide compound found in almond, peach pits, and some other stone fruits. Fun fact: “amygdala,” like in your brain, comes from the same Greek root as amygdalin. Here, it describes the source of the compound, in “amygdala,” it describes the shape of the structure. Sort of like naming the pituitary “Mr. Peanut,” then translating it into a dead tongue for some added class.

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This is the yellow pigment in turmeric, the spice responsible for curries being nuclear holocaust yellow.

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Here’s a neat and weekend-appropriate one. I’ve alluded to the fact that your body processes small amounts of endogenous alcohol in the course of metabolism. As such, you have evolved some enzymes to process ethanol. The enzymes are meant for ethanol, since that’s what organisms saw for the most part in the course of evolution. As we’ve seen with drugs and poisons, though, other molecules can fit just fine into the active pocket of an enzyme and it can do its business on them, too. Sometimes this works in your favor, sometimes not. In the case of alcohol, it’s great. If you didn’t have a processing enzyme, it would be much more harmful than it is; it would have to wait around to pass through your urine (it could fit into a few other enzymes, but not very well; I believe this is the major alternative pathway).

What happens is your body takes alcohol and begins to oxidize it. Ethanol turns into acetaldehyde, which turns into acetic acid, which your body knows how to handle fine. The ethanol to acetaldehyde step is catalyzed by the enzyme alcohol dehydrogenase and requires one NAD+ (nicotinamide adenine dinucleotide, an endogenous oxidizing agent involved in glycolysis. The acetaldehyde to acetate step also requires NAD+ and is catalyzed by aldehyde dehydrogenase.
Relative to Anglos, many Asians have a paucity of aldehyde dehydrogenase, causing acetaldehyde to build up when ethanol is consumed. This causes the flushed face seen in many Asians after even moderate alcohol consumption. In all populations, NAD+ is limiting; your body simply does not have that much. It is regenerated, but slowly, so even after moderate alcohol consumption, NADH (the metabolite of NAD+) to NAD+ regeneration is the limiting step in the alcohol to acetate cycle. This is poorly understood — understandably. Not many research dollars get routed to hangover prevention, since it’s essentially a nuisance and considered a “disease of excess.”
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In what seems to be de rigeur for artificial sweeteners, sucralose (Splenda) was discovered by accident, when some careless soul tasted it. From Wikipedia:

Sucralose was discovered in 1976 by scientists from Tate & Lyle, working with researchers at Queen Elizabeth College (now part of King’s College London). It was discovered by Leslie Hough and a young Indian chemist Shashikant Phadnis. The duo were trying to make an insecticide. On a late-summer day, Phadnis was told to test the powder. Phadnis thought that Leslie asked him to taste it; so he did. He found the compound to be ridiculously sweet (the final formula was 600 times sweeter than sugar). They worked with Tate & Lyle for a year before settling down on the final formula. They did not find any use of the compound as an insecticide.

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GHB stands for gamma-hydroxybutyrate. It has received buckets of terrible press in recent years that would certainly have resulted in lawsuits in both directions if it was a patented pharmaceutical. Let’s take a look at the structure, then we will take a look at the days of yore when GHB was a blameless little molecule you bought at GNC (or you could get from Aldrich for organic synthesis). Then, we’ll take a look at the subsequent demonization and where we stand today.

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So, as we mentioned yesterday, good old Thomas Midgley had made quite a mess of things with his organolead snafu. By way of apology, he gave us CFCs. Why would we want them?

To make a refrigerator, you need a gas that can go pretty easily between liquid and gas - so, something with a near-room temperature boiling point at atmospheric pressure. If you’re a chemist, you’re thinking: ether, anhydrous ammonia, sulfur dioxide, and a bunch of other nasties. That was, in fact, the stuff we used first (Well, not ether. But loads of SO2 and NH3). Trouble was, it was so toxic it kept killing people. We needed something that balanced volatility with low toxicity.

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Friday, we talked about about carvone. I mentioned that it comes from the same biosynthetic pathway as cholesterol. The precursor to this, as well as a number of other natural products, is isopentenyl pyrophosphate, which we’ll refer to as IPP:

A few things this ends up in are compounds like carvone, limonene, and menthol, shown below:

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The other day we talked chirality. Here’s the example they give in every organic chemistry class when they’re teaching chirality. Carvone!

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Have you ever wondered whether you would swim faster in syrup or water? I hadn’t, either, until I found out someone had actually brought a swimming pool up to to Mrs. Butterworth’s-level viscosity and had people swim in it. Then I became intensely curious.

Proell admits he was slightly taken aback when he first heard Cussler’s proposal to dump 700 pounds of guar gum, a thickening agent, into one of the University’s pools. Fortunately, though, he recognized the proposal’s educational merits.

“Cussler is persuasive, but we didn’t need much persuading. We all agreed that we had an opportunity here to be part of the University’s educational mission. [The experiment] involved movement through water. [I]n aquatics, that’s our business. It intrigued us.”

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