Riboflavin binding proteins

In pregnant women, there is a progressive increase in the erythrocyte glutathione reductase activation coefficient (an index of functional riboflavin nutritional status Section 7.5.2), which resolves on parturition despite the daily secretion of 200 to 400 /rg (0.5 to 1 /rmol) of riboflavin into milk. This suggests that the estrogen-induced riboflavin binding protein can sequester the vitamin for fetal uptake at the expense of causing functional deficiency in the mother. 

In laying hens, induction of this riboflavin protein results in a 100-fold increase in plasma riboflavin, compared with males or nonlaying females. In mutant chickens lacking the protein, the adult has massive urinary loss of riboflavin. The embryo develops normally for about 10 days, then develops severe hypoglycemia associated with a reduction in medium-chain acyl coenzyme A (CoA) dehydrogenase to 20% of normal activity and the accumulation of intermediates of fatty acid oxidation (White, 1996). 

The riboflavin binding protein that occurs in eggs has been exploited for the radio-ligand binding assay of riboflavin. Because binding to the protein quenches the native fluorescence of riboflavin, it can be exploited for a direct titrimetric fluorescence assay of the vitamin in urine and other biological samples (Kodentsova et al., 1995). 

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F. K. Ogasawara, Y. Wang, and D. R. Bobbitt, Dynamically modified, biospecific optical fiber sensor for riboflavin binding protein based on hydrophobically associated 3-octylriboflavin, Anal Chem. 

E DeLorenzi, G Massolini. Riboflavin-binding proteins as chiral selectors in HPLC and CE. Pharm Sci Technol Today 2 352-364, 1999. 

E DeLorenzi, G Massolini, M Quaglia, C Galbusera, G Caccialanza. Evaluation of quail egg white riboflavin—binding protein as a chiral selector in capillary electrophoresis by applying a modified partial-filling technique. Electrophoresis 20 2739-2748, 1999. 

Mieloszyk and colleagues [226] determined that flavins which form charge-transfer complexes with proteins exist in both the ground and excited electronic states. In the flavin-riboflavin-binding protein the trytophan is considered to be the donor. Other such complexes of flavin coenzymes and apoenzymes are known [227-229]. 

The administration of thyroid hormones to hypothyroid animals results in a rapid increase in flavokinase activity as a result of the activation of an inactive precursor protein as flavokinase activity increases, there is a parallel decrease in the tissue content of an apparendy inactive riboflavin binding protein (Lee and McCormick, 1985). 

Over the years, a wide variety of diverse proteins have been tested for their potential to serve as the SOs of novel CSPs with different application profiles. For example, flavoprotein 216], avidin and conalbumin [217], as well as other proteins like egg-yolk riboflavin binding protein [218], have been immobilized onto silica. However, neither their enantioselectivity profiles nor their performance was significantly better than those of commercially available protein type CSPs. 

Merrill, A. H., Frochlich, J. A-, and McCormick, D. D. (1979). Purification of riboflavin-binding proteins from bovine plasma and discovery of a pregnancy-specific riboflavin-binding protein,. Bioi. Chem. 254,9362-9.364. 

Merrill AH, Froehiich JA, McCormick DB. Isolation and identification of alternative riboflavin-binding proteins from hmnan plasma. Biochem Med 1981 25 198-206. 

De Lorenzi, E., Massolini, G., I.loyd, D. K., Monaco, H. L., Galbusera, C., Caccia-lanza, G. Evaluation of quail egg white riboflavin binding protein as a chiral selector in high-performance liquid chromatography and capillary electrophoresis, J. Chromatogr. A, 1997, 790, 47-64. 

Calleri, E., De Lorenzi, E., Siluk, D., Markuszewski, M., Kaliszan, R., Massolini, G. Riboflavin binding protein — chiral stationary phase investigation of retention mechanism, Chromatographia,... 

When riboflavin (RF) is mixed with riboflavin binding protein from egg white, the fluorescence intensity decreased to about two-thousandth. Transient absorption spectra of riboflavin binding protein were also measured with the picosecond laser photolysis technique (14), as shown in Fig.8. The transient behavior of the spectra was quite different from that of flavodoxin. 

Fig. 8. Transient absorption spectra of riboflavin binding protein from egg white. Delay times from pulsed excitation are shown in the Fig. (14).

Massolini, G. De Lorenzi, E. Ponci, M.C. Gandini, C. Caccialanza, G. Monaco, H.L. Egg yolk riboflavin binding protein as a new chiral stationary phase in high-performance liquid chromatography. J.Chromatogr.A, 1995, 704, 55-65... 

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