My recent DNA #nucleobase etymology thread turned out to be surprisingly popular. So now let's do the amino acids -- #HematologyTweetstory 12. This pretty chart of the #aminoacids is from “BioNinja”: ib.bioninja.com.au/standard-level… 
Knowing word origins isn't essential to using terms well, but these histories can be interesting and illuminating. So, while you may not be a bodybuilder💪🏋️♂️🏋️♀️ who eats amino acids to bulk up, you can read #HematologyTweetstory 12 to build up your “body of knowledge". 😉
Let’s start with #Arginine, “the pirate’s favorite AA” (Arrrr!)🤪, first isolated by Ernst Schulze in Zürich (1886) from lupin seeds. His arginine crystals looked silvery; the Greek word árgyros (ἄργυρος)=silver. Argentina, rich in silver ore, gets its name from the same root./2
Schulze also discovered 2 other amino acids: 1) #Phenylalanine (1879), which has a phenyl- group (more about phenyl- and #Alanine below) and 2) #Glutamine (1883), which he originally got from sugar beet juice (hence the glu- prefix, which means sugary and is from Greek γλυκός)./3
#Glycine has a similar name origin to #Glutamine & shares the same glu-/gly- root. It was discovered (1820) by Henri Braconnot in Nancy, France by boiling gelatin with sulfuric acid. He called it “sugar of gelatin”. Swedish chemist Jöns Jacob Berzelius proposed the simpler name.
#Alanine was discovered in 1850 by Adolph Strecker (pictured), who was working w/ Justus Liebig in Gießen, Germany. Strecker started w/ acetaldehyde & ammonia; the ala- is from aldehyde. Liebig himself coined aldehyde, from Latin alcohol dehydrogenatus (dehydrogenated alcohol).
And the “phenyl” of #Phenylalanine mentioned above is ultimately from the Greek φαίνω (phaínō, “I shine"), since the first phenyl ring was isolated in 1825 from sooty residue obtained from London’s shiny street lamps, by the brilliant Michael Faraday./6
#Valine came from casein, but is chemically similar to valeric acid, from the medicinal herb valerian (Latin valere = to be strong, healthy). It was isolated in Berlin by Emil Fischer, 1902 Nobel chemistry laureate, who described numerous other molecules (eg caffeine, uric acid.)
#Cysteine was 1st isolated from a bladder stone (!) in 1810 by Englishman William Wollaston. He called it "cystic oxide"; Berzelius simplified this, too, to cystine, & German Eugen Baumann to cysteine in 1884. Cysto=bladder. (For non-medical folks: Bladder infection = cystitis.)
#Proline, discovered in 1900 by Richard Willstätter (below, L) in Munich, has a pyrrol- ring. The origin is Greek: pyrrhos (πυρρός)= “reddish, fiery”, from the rxn used to detect pyrrole in coal tar by F.F. Runge (below, R) in 1834. Not sure where the -yr- went in pyrolline/10
#Leucine was one of the first AA discovered, isolated from spoiled cheese in 1810 by Frenchman Joseph-Louis Proust, who was working in Salamanca. This set a trend for isolating amino acids from cheese or casein. Proust called it leucine (Gr.) because the crystal form was white.
Getting to #Isoleucine required the ability to separate racemic AAs. This was 1st done in 1903 by Felix Ehrlich at the “Institute of the Sugar Industry” in Berlin. He used red blood cells as a protein source (not white cells=leukocytes, which would have been more appropriate)!/12
#Methionine was isolated relatively late in the scheme of things: in 1921 by American bacteriologist @Columbia John Howard Mueller. The me- is from methyl (methy=wine and hyle=wood in Greek, since it came from wood alcohol) while thio = sulfur. It's a simple chemical description.
Remember Albrecht Kossel (L) who discovered several nucleobases? He also discovered #Histidine (1896), as did Sven Gustaf Hedin independently (below R). Histidine is uncreative in the way DNA cytosine was. It is from tissues (similar origin to "histology", study of tissues)./14
I haven't included many asides/tangents since threads are limited to 25 & there are 20 canonical AAs. But will say the only exam I ever failed was a 1st year histo exam; I skipped studying to drive to Michigan to ask my girlfriend to marry me. Excusable, don’t you think?🙂 /15
Back to the amino acids. #Lysine also came from tissues, but tissues undergoing decomposition (lysis) - i.e., rotten cheese. This isolation was by well-bearded Ferdinand Heinrich Edmund Drechsel in 1889./16
#Threonine was the last of the 20 standard/canonical amino acids to be discovered, in 1930 by American biochemist William Cumming Rose (1887-1985) at @Illinois_Alma. It is similar to the sugar threose, which is related to erythro- prefix (story too complex to get into here)./17
#Asparagine… really did come from asparagus juice. It was the among the first amino acids to be isolated, in 1806 by Pierre Robiquet and Louis Vauquelin in Paris. Robiquet also discovered codeine, and Vauquelin discovered beryllium and chromium – not a bad pair of CVs! /18
The 2 negatively charged amino acids are related to those we've already discussed. #AsparticAcid is derived from asparagine, and #GlutamicAcid from glutamine. Here's a 1931 summary of amino acid discoveries by Vickery & Schmidt, one of many sources I used for this thread./19
By now you may be getting weary😴 so let’s finish with sleep-inducing #Tryptophan, first isolated from casein by Frederick Hopkins (1861-1947) & named by R.Neumeister in 1890. It literally means “to be broken and to appear” since it “appeared” (phano-) after trypsin digestion./20
One of the learning tasks for biochem students is memorizing the 1-letter AA abbreviations. For this we can thank/blame @Georgetown Professor Margaret Oakley Dayhoff (1925-1983), a bioinformatics pioneer. A nice summary of why she picked those letters: biology.arizona.edu/biochemistry/p… /21
Incidentally, many amino acids were either renamed by German chemist Justus von Liebig, discovered by his students/colleagues, or further purified by him. And that gives me the chance to spell his name correctly (!), which I neglected to do in my #nucleobase #Tweetstory 🤷♂️/End
