Oestrogen induction of riboflavin-binding protein in immature chicks. Nature of the secretory protein

Abstract

The riboflavin-binding protein isolated from sera of oestrogen-treated male chicks as well as that synthesized and secreted in vitro by the chicken liver have the same molecular size as that of the egg-yolk protein. Functionally the serum and yolk proteins are similar. This is in contrast with the hormone-induced synthesis, secretion and deposition of phosvitin and lipovitellin in the ovary.

Riboflavin carrier protein: A serum and tissue marker for breast carcinoma

“…14 The monoclonal antibodies (MAbs) to chicken RCP used in this investigation have been described earlier and shown to cross-react with purified mammalian, including human, RCP. 15,16 Serum samples Serum samples were collected for routine laboratory investigations from 43 breast cancer patients from the Kidwai Memorial Institute of Oncology, Bangalore, India (Study I, 1986/87) and from 47 breast cancer patients from the Bangalore Institute of Oncology, Bangalore, India (Study II, 1995/96).…”

Isolation and characterization of thiamin-binding protein from chicken egg white

“…The flavin-binding capacity was determined by saturating the gel-bound protein (used as a column, 5 ml bed volume) with riboflavin. After the excess of flavin was washed off completely with 0.1 M-sodium phosphate buffer (pH 7.0)/1 M-NaCI, that held by the immobilized protein was eluted with 0.1 M-sOdium citrate buffer, pH 3.0 (Murthy & Adiga, 1978), and quantified spectrophotometrically by using e = 1.25 x 104M-1 cm-' (Whitby, 1953) and by assuming a 1:1 molar stoicheiometry of the ligand-protein interaction (Murthy et al, 1976).…”

“…For this, 1.0ml of the sample protein (1 mg) in 0.1 M-sodium phosphate buffer, pH7.0, was allowed to equilibrate for 48h at 30°C with various known concentrations of [14C]thiamin in the same buffer. After the establishment of equilibrium, the radioactivities in both the compartments of the dialysis cell were quantified by liquid-scintillation spectrometry by using a Beckman LS-100 instrument (Murthy & Adiga, 1978). Protein was measured by the method of Lowry et al (1951), with bovine serum albumin as the standard.…”

“…(2) on double-immunodiffusion analysis on agar against monospecific antiserum to riboflavinbinding protein (Murthy & Adiga, 1977) it gave a single precipitin line confluent with that corresponding to the purified riboflavin-binding protein (Fig. 3); (3) the flavin could be dissociated by exposure to sodium citrate buffer (pH 3.0) and separated from the apoprotein by gel filtration on Sephadex G-25 and identified as riboflavin by paper chromatography (Murthy & Adiga, 1978). The apoprotein thus obtained could quench flavin fluorescence when a fixed concentration of the protein was titrated spectrofluorimetrically (Nishikimi & Kyogaku, 1973) against thiamin pyrophosphate-aminoethyl-Sepharose The column (1 .2cm x 8cm) was pre-equilibrated with O.1lM-sodium phosphate buffer, pH 7.0.…”

A comparative analysis of the evolution of the egg envelopes and the origin of the yolk

“…Livetins represent a group of highly heterogeneous (McIndoe & Culbert, 1979;Wallace, 1978;\Villiams, 1962), watersoluble proteins most of which have their counterpart in the serum, such as albumin, a2-glycoprotein, transferrin and y-globulins. I n addition some proteins with a specific micro-nutrient carrier role have also been described, such as biotin-binding protein (White et al, 1976) thiamin-binding protein (Muniyappa & Adiga, 1980& Adiga, , 1981, riboflavin-binding protein (Murthy & Adiga, 1978;Steczko & Ostrowski, 1975) and retinol-binding protein (Heller, 1976).…”