#Id: 4716

#Unit 13. Methods in Biology

Proteins that contain prosthetic groups (e.g. haem, flavin, carotenoid) and some metal–protein complexes, may have strong absorption bands in the UV/Vis range.

#Id: 4717

#Unit 13. Methods in Biology

n. Carotenoids, for instance, are a large class of red, yellow and orange plant pigments composed of long carbon chains with many conjugated double bonds. They contain three maxima in the visible region of the electromagnetic spectrum (420 nm, 450 nm, 480 nm).

#Id: 4718

#Unit 13. Methods in Biology

Electron delocalisation extends throughout the cyclic tetrapyrrole ring of porphyrins and gives rise to an intense transition at 400 nm called the Soret band.

#Id: 4719

#Unit 13. Methods in Biology

Molecules such as FAD (flavin adenine dinucleotide), NADH and NADþ are important coenzymes of proteins involved in electron transfer reactions (RedOx reactions). They can be conveniently assayed by using their UV/Vis absorption: 438 nm (FAD), 340 nm (NADH) and 260 nm (NADþ).

#Id: 4720

#Unit 13. Methods in Biology

#Id: 4721

#Unit 13. Methods in Biology

The absorption spectra of the bases in polymers are sensitive to pH and greatly influenced by electronic interactions between bases.