Monday, January 21, 2013

Thanks to SAMJ (the SOUTH AFRICAN MEDICAL JOURNAL), we can learn of first published guess as to penicillin's chemical structure

SAMJ : the South African Medical Journal
So much has been written about the earliest days of trying to determine the chemical structure of pure penicillin, in such truly massive tomes like "THE CHEMISTRY OF PENICILLIN" and "ANTIBIOTICS,VOLUME II", and much more delightfully in John Sheehan's lucid-but-learned "THE ENCHANTED RING" , that there seems little more to add.

But that is not so, thanks to the South African medical journal SAMJ and its enterprise at putting all of its over 100 years of back issues online and free to access.

It is little known that Karl Meyer, the chemist on the tiny pioneering Columbia university team ( the first ever to use penicillin as an antibiotic), contributed an unique intellectual portion to Henry Dawson's first presentation on penicillin.

This presentation was delivered in Atlantic City, at the 33rd annual meeting of the American Society for Clinical Investigation, ( the famous "Young Turks" ) May 5th 1941 --- attended by top medical researchers from all over the world and covered by the scientific and popular media.

To add to the journalistic fun, their more senior and sober counterparts, the American Association of Physicians, met the very next day in the same place - and the two generations of doctors didn't always agree on everything, naturally .

Most penicillin historians seemed to have limited their knowledge of this seminal event to the New York Times report on it, easily available anywhere on microfilm.

But the official abstract of Dawson's presentation , formally published in the Journal of the Society in July 1941, mentions - in passing - two important subject areas that all the popular media left out in describing Dawson's paper.

His presentation talked of the methods of preparation ( and importantly made it clear this took place in Dawson and Meyer's hospital lab and not in some drug company lab), without saying anything more.

 Fortunately later articles do amplify on the earliest methods of growing and extraction in great detail.

But the precis also indicates that information as then known of penicillin's chemical nature , ie known as of late 1940-early 1941 , was discussed --- without saying what was speculated.

This speculation is NOT repeated in any later article, because this early speculation was not even close to penicillin's final chemical structure, as found with the help of hundreds of chemists, five long gruelling years later.

But, while I am not a chemist, I think I can say it wasn't a bad guess for what was known - almost by sight and smell - about the earliest dry penicillin powder.

Thanks to SAMJ, the South African Medical Journal

But back to SAMJ - because it was all down to one of their most enterprising correspondents , H O Hofmeyr, that we know anything at all about the earliest chemistry of penicillin.

Hofmeyr came from a very politically powerful Afrikaner family and so it is not surprising he was sent abroad, during WWII, to be South Africa's scientific eyes and ears in places like Washington DC.

He wrote a very complete diary of his visit to the Clinical Investigators annual meeting and it was published, in full ,in the September 1941 monthly issue of SAMJ.

I think I remain the only one to ever cite Hofmeyr's eyewitness report on the opening of the Age of Antibiotics.

I have always treasured his report on Dawson's paper , partly for his slightly snide tone relating that this particular paper caught the imagination of ("sniff") the ("popular") press who gave it ("lurid") headlines like 'Giant Germicide Yielded by Mold'.

But in addition, Dr HO ( as everyone called him) correctly noted in 1941 what current historians always, always miss : that Dawson's use of penicillin on subacute bacterial endocarditis, the dreaded SBE, was in some ways, highly conventional.

Hofmeyr said it still remained in 1941, the absolute "acid test" for the claims of every new potential chemotherapeutic agent.

But buried in middle of the paragraph, Hofmeyr indicates that the Columbia team is willing to speculate publicly that penicillin seems related to the hydroquinones.

The hydroquinones are a big family best known for their use in photo developing and skin whitening, but one in particular, paraquinone ,strikes me as looking, smelling and acting rather like early penicillin powder.

Yellow , arid penetrating smell, very sensitive to acids and bases, yes it sure does look, smell and act like early penicillin.

But paraquinone has only has about one third the molecular weight and number of atoms that penicillin has (and was thought to have in 1941) so it would have to be quite an elaborated version to fit the known facts.

WE have to wait to 1942 and the much better known journals such as NATURE and SCIENCE to find the next set of informed guesses as to penicillin's structural nature, but thanks to SAMJ, we have recovered an important fragment of medical history .....

No comments:

Post a Comment