Enzymes are biological catalysts that allow a host of chemical reactions to take place in organisms. They can also be used in synthetic chemistry to perform difficult reactions, e.g., forming carbon-carbon bonds. Enzymes (and more generally, all catalysts) do this by lowering the activation energy of a reaction and stabilizing the transition state. Where does the word enzyme come from?

Origin: Greek, en– (in) + zyme (leavened)
Something leavened in

Louis Pasteur (Pasteur pipettes, pasteurization, etc.), a titanic French chemist of the 1800s, was studying the fermentation of alcohol by yeast.  He postulated that the agent responsible for fermentation was a “vital force,” and that only living organisms could perform the task. Wilhelm Kühne coined the term “enzyme” to refer to the process, but it was Eduard Büchner (Büchner funnel) who showed that cell-free yeast extracts could still ferment sugar into alcohol. For this, Büchner received the 1907 Nobel Prize in Chemistry. He named the agent responsible zymase.

pasteur and buchner

Left: Pasteur; Center: Kühne; Right: Büchner

Origin: Greek, zyme (leavened) + –ase (enzyme suffix)
That which cleaves “leavened,” i.e., the substrate is from the yeast

Following Büchner’s convention, we use the suffix –ase to denote the substrate of an enzyme, e.g., an enzyme that catalyzes a reaction involving a peroxide is called a peroxidase. Note that this convention is not used for all enzymes. Here are some enzymes with interesting etymologies that are important for digestion:

Origin: Greek, a– (without) + myle (mill) + –ase
That which cleaves something unmilled, i.e., starch

Origin: Greek, peptein (to digest)
That which cleaves proteins into peptides

Origin: Greek, lipos (fat) + –ase
That which cleaves fats, e.g., triglycerides

Some enzymes require organic or inorganic cofactors in order to function. The organic cofactors can either be prosthetic groups, which are covalently bound to the enzyme, or they can be coenzymes, which are cleaved from the active site during the reaction. Some cofactors may be involved in allosteric modulation; here, an ion or molecule binds to an area away from the enzyme’s active site to modulate its activity.

biotin cofactor

Biotin (left) is a cofactor of pyruvate carboxylase (right)

Origin: Greek, allos (other) + stereos (solid, taken to mean 3D shape/position)
Pertaining to another space/position

Are there any cool enzymes with puzzling etymologies that you can think of? Leave a comment below and let’s explore!

When learning organic chemistry, one of the first topics presented is the naming of organic compounds. The International Union of Pure and Applied Chemistry (IUPAC) codified its recommendations in A Guide to IUPAC Nomenclature of Organic Compounds in 1900. Since then, it has been constantly revising its naming schema for both organic and inorganic compounds. Students of organic chemistry also learn the original nomenclature (“common” nomenclature) for some compounds and groups. First of all, what is the etymology of nomenclature?

Origin: Latin, nomen (name) + culator (one who calls; from calare, to call)
A calling by name

The IUPAC, for one- and two-carbon alkyl substituents, kept the original nomenclature. For the three- and four-carbon alkyl substituents, they modified them slightly. The rest of the substituents have new standard names, but in many instances, especially in biochemistry, the original names are kept. A few of these names beg for an etymological breakdown.

-CH3; methyl
Origin: Greek, methu (wine) + hule (wood)
Wood spirits/wood alcohol; methanol is a byproduct when destructively distilling wood

-C2H5; ethyl
Origin: Latin, aether (upper air) + -yl (shorter form of hule)
Back-named from (diethyl) ether, for its very low boiling point

-C3H7; propyl
Origin: Greek, pro– (first) + pion (fat) + –yl
First fat, from Dumas’s observation that propionic/propanoic acid is smallest carboxylic acid to display the properties of other fatty acids

linoleic acid revBonus: linoleic [Origin: Greek, linon (flax) + oleum (oil)]

-C4H9; butyl
Origin: Latin, butyrum (butter) + –yl
So named from the fact that rancid butter contains butyric/butanoic acid

-C5H11; pentyl
Origin: Latin, penta– (five) + -yl
Five carbons in the alkyl group

And starting with pentyl, the rest of the alkyl groups are named by Latin numbers. Sad…