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Tuesday, January 31, 2012

Monday's Molecule #157

You need to pay close attention in order to identify this molecule correctly.

Post your answer in the comments. I'll hold off releasing any comments for 24 hours. The first one with the correct answer wins. I will only post correct answers to avoid embarrassment.

There could be two winners. If the first correct answer isn't from an undergraduate student then I'll select a second winner from those undergraduates who post the correct answer. You will need to identify yourself as an undergraduate in order to win. (Put "undergraduate" at the bottom of your comment.)

Some past winners are from distant lands so their chances of taking up my offer of a free lunch are slim. (That's why I can afford to do this!)

In order to win you must post your correct name. Anonymous and pseudoanonymous commenters can't win the free lunch.

Winners will have to contact me by email to arrange a lunch date.

UPDATE: The molecule is L-sedoheptulose 1,7-bisphosphate or L-altro-hept-2-ulose 1,7-bisphosphate. The D isomer is part of the pentose phosphate cycle and the Calvin cycle. The winner is Peter Monaghan.

Nov. 2009: Jason Oakley, Alex Ling
Oct. 17: Bill Chaney, Roger Fan
Oct. 24: DK
Oct. 31: Joseph C. Somody
Nov. 7: Jason Oakley
Nov. 15: Thomas Ferraro, Vipulan Vigneswaran
Nov. 21: Vipulan Vigneswaran (honorary mention to Raul A. Félix de Sousa)
Nov. 28: Philip Rodger
Dec. 5: 凌嘉誠 (Alex Ling)
Dec. 12: Bill Chaney
Dec. 19: Joseph C. Somody
Jan. 9: Dima Klenchin
Jan. 23: David Schuller


  1. L-altro-hept-2-ulose 1,7-bisphosphate

    Peter Monaghan

  2. Molecule # 157 is L-sedoheptulose 1, 7-bisphosphate

  3. Hmm a tricksy one. There arent many naturally occurring heptoses (C7 sugars) which narrows things down a bit. Assuming you are using standard Fischer projection, this compound is "L-altro-heptulose-1,7-bisphosphate", i.e. the unnatural enantiomer of sedoheptulose, esterified twice with phosphoric acid.

    Pedantic Chemist forsees some people will be tricked up by trying to compare the Fischer projection above, with the zigzag representation given on the wikipedia page for sedoheptulose.

  4. It appears to be sedoheptulose-1,7-bisphosphate, an intermediate of the Calvin cycle.
    You appear however to show the L-stereoisomer, whereas it is the D-stereoisomer that is involved in the Calvin cycle

  5. L-altro-hept-2-ulose 1,7-bis(dihydrogen phosphate), and you may call me the grand poobah of the Internets.

  6. Hi Larry,

    There is no L isomer of sedoheptulose: according to IUPAC definitions on the Nomenclature of Carbohydrates ( ):
    "Sedoheptulose is the accepted trivial name for D-altro-hept-2-ulose."

    This is why I was so specific in naming the molecule not as L-sedoheptoluse 1,7-bisphopshate but L-altro-hept-2-ulose bisphopshate.


    1. I think "glucose" is the accepted trivial name for D-glucose but that doesn't mean there's no L-glucose. It just means that you can't refer to The L-isomer using the trivial name alone.