2011-02-25, 10:03 PM
Well, this is kinda out of my syllabus, but I just wanted to know...
Histidine is an alpha-amino acid with an R group that resembles cyclopentane, except that two of atoms in the ring are Nitrogen atoms (at the 2 and 4 positions) instead of Carbon atoms. One of these two Nitrogen atoms (this one's at the 4 position) forms a double bond with an adjacent Carbon atom, and a single bond with another adjacent Carbon atom. The other Nitrogen atom (this one's at the 2 position) forms only single bonds with its two adjacent Carbon atoms, and has a Hydrogen atom attached to it.
My question is, when placed in a highly acidic solution, which one of these two Nitrogen atoms will accept a Hydrogen ion (my Chemistry teacher confirmed that only one of them will accept an ion, but refused to divulge any more information)?
My guess is that the Nitrogen atom with the double bond will accept the Hydrogen ion, because the high electron density within the double bond will attract the positively-charged Hydrogen ion...is this correct?
Histidine is an alpha-amino acid with an R group that resembles cyclopentane, except that two of atoms in the ring are Nitrogen atoms (at the 2 and 4 positions) instead of Carbon atoms. One of these two Nitrogen atoms (this one's at the 4 position) forms a double bond with an adjacent Carbon atom, and a single bond with another adjacent Carbon atom. The other Nitrogen atom (this one's at the 2 position) forms only single bonds with its two adjacent Carbon atoms, and has a Hydrogen atom attached to it.
My question is, when placed in a highly acidic solution, which one of these two Nitrogen atoms will accept a Hydrogen ion (my Chemistry teacher confirmed that only one of them will accept an ion, but refused to divulge any more information)?
My guess is that the Nitrogen atom with the double bond will accept the Hydrogen ion, because the high electron density within the double bond will attract the positively-charged Hydrogen ion...is this correct?