Study on the Conjugation of Cortisol in the Lens

Ono, Satoshi; Hirano, Hiroko; Obara, K

doi:10.1159/000266221

Cited by 7 publications

(4 citation statements)

References 1 publication

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Riboflavin undergoes complex photochemical reactions with proteins in vivo. Photolysis of RB in the lens of the eye leads to the formation of flavin-ocular protein adducts. , Photolysis of RB in plasma (which transpires when jaundiced newborns are treated for hyperbilirubinemia) produces a flavin-albumin adduct. − The structures of these adducts are not known, but it has been determined that tryptophan residues are involved in this linkage . It seems likely that adduct formation involves the triplet state of the flavin because adduct formation is quenched by 10 mM ascorbate ion …”

Section: Introductionmentioning

confidence: 99%

The Reaction of Triplet Flavin with Indole. A Study of the Cascade of Reactive Intermediates Using Density Functional Theory and Time Resolved Infrared Spectroscopy

et al. 2002

View full text Add to dashboard Cite

As a model for riboflavin, lumiflavin was investigated using density functional theory methods (B3LYP/6-31G* and B3LYP/6-31+G**) with regard to the proposed cascade of intermediates formed after excitation to the triplet state, followed by electron-transfer, proton-transfer, and radical[bond]radical coupling reactions. The excited triplet state of the flavin is predicted to be 42 kcal/mol higher in energy than the singlet ground state, and the pi radical anion lies 45.1 kcal/mol lower in energy than the ground-state flavin and a free electron in the gas phase. The former value compares to a solution-phase triplet energy of 49.8 kcal/mol of riboflavin. For the radical anion, the thermodynamically favored position to accept a proton on the flavin ring system is at N(5). A natural population analysis also provided spin density information for the radicals and insight into the origin of the relative stabilities of the six different calculated hydroflavin radicals. The resulting 5H-LF* radical can then undergo radical[bond]radical coupling reactions, with the most thermodynamically stable adduct being formed at C(4'). Vibrational spectra were also calculated for the transient species. Experimental time-resolved infrared spectroscopic data obtained using riboflavin tetraacetate are in excellent agreement with the calculated spectra for the triplet flavin, the radical anion, and the most stable hydroflavin radical.

show abstract

Section: Introductionmentioning

confidence: 99%

The Reaction of Triplet Flavin with Indole. A Study of the Cascade of Reactive Intermediates Using Density Functional Theory and Time Resolved Infrared Spectroscopy

et al. 2002

View full text Add to dashboard Cite

show abstract

“…Furthermore, the liver is the organ primarily responsible for the catabolism of the steroid hormone (19). It may be thought that changes in the liver function could either directly or indirectly influence the steroid hormone metabolism in the lens as reported previously (20), and finally it would bring about a reduction in the synthesis of cortisol-binding protein in the lens.…”

Section: Discussionmentioning

confidence: 79%

“…We have demonstrated that cortisol binding by lens protein is carried out fairly actively leading to inactivation of steroid hormone in the lens (1).…”

mentioning

confidence: 92%