NAD+ / NADH Question: Absorption peaks and spectra

  • #1
Jake578

Main Question or Discussion Point

Hi guys,

Im new here so im going to get right to it. Excuse my grammer I am on my mobile.

So I am trying to understand the difference in absorbance spectra of NAD+ and NADH. I have seen this touched on on this site but not directly answered.

NAD+, with an apparent two aromatic structures, produces one spectral peak.

NADH, with an apparent singular aromatic structures, produces two spectral peaks.

Now I believe for abs. a molecule must have aromatic structures... I have a feeling perhaps resonance structures in both molecules are causing the number of spectra not to match the number of aromatic structures?

What are your thoughts?

Jake
 

Answers and Replies

  • #2
Jake578
Bump
 
  • #3
DrDu
Science Advisor
6,032
759
Each of the broad peaks you see in the spectrum (UVVis for sure) correspond to dozens of different transitions in the molecules this becomes apparent once you look at carefully taken spectra at the temperature of liquid nitrogen and there is not only one aromatic molecule present but several, so that a detailed assignment isn't possible.
My best guess is that the second bump in NAD+ is due to a charge transfer transition involving the N+.
 
  • #4
TeethWhitener
Science Advisor
Gold Member
1,769
1,126
The peak at 260 nm in both spectra is the adenine ##\pi\to\pi^*## transition. The NAD+ does have a second peak for the aromatic pyridine ring ##\pi\to\pi^*## transition, but it's deeper in the UV (I think around 220 nm or so). The peak at 340 nm that appears in the NADH is (if I recall correctly), usually assigned to the ##n\to\pi^*## transition of the conjugated ketone/alkene structure (cf. the broad resonance at around 340 nm in acrolein: http://webbook.nist.gov/cgi/cbook.cgi?ID=C107028&Mask=400#UV-Vis-Spec).
 
Last edited:
  • Like
Likes jim mcnamara and Ygggdrasil

Related Threads on NAD+ / NADH Question: Absorption peaks and spectra

Replies
4
Views
10K
  • Last Post
Replies
0
Views
3K
  • Last Post
Replies
8
Views
15K
  • Last Post
Replies
3
Views
1K
  • Last Post
Replies
2
Views
6K
Replies
1
Views
2K
Replies
2
Views
2K
Replies
1
Views
3K
Replies
2
Views
7K
  • Last Post
Replies
1
Views
2K
Top