氨基酸的光化学诱导动态核极化

维生素B₂与氨基酸和氨基酸衍生物水溶液体系的光化学诱导动态核极化(photo chemically induced dynamic nuclear polarization, CIDNP)研究表明,在维生素B₂作为光敏化剂的体系中,N-乙酰-L-酪氨酸和N_α-乙酰-L-组氨酸显示很强的极化信号,而其它氨基酸和衍生物则未观察到。

PHOTOCHEMICALLY INDUCED DYNAMIC NUCLEAR SPIN POLARIZATION OF AMINO ACIDS

A photochemically induced dynamic nuclear spin polarization (photo-CIDNP) study was presented of the amino acids that are polarisable with vitamin B? In the amino acid-vitamin B?systems with light irradiation, strong emission for 3-H, 5-H and enhanced absorption for 2-H, 6-H at the benzene ring of N-acetyl-L-tyrosine and enhanced absorption for the protons at the imidazole ring of N-acetyl-L-histidine were observed. No polarization was observed for other protons or protons at other amino acids and deriveatives. The CIDNP evidence indicates that the hydrogen-atom abstraction is important in generating radical pairs in the vitamin B₂ sensitizing systems. Vitamin B₂ was considered to be an excellent sensitizer and probe for the surface amino acid residues of proteins and enzymes.