High impact information on LOC396449

• Riboflavin binding protein (ribBP) is an essential component of chicken eggs; it supplies the oocyte (i.e. yolk) and egg white with sufficient amounts of the vitamin riboflavin to sustain embryonic development until hatching [1].
• A series of partially dephosphorylated yolk RBP samples, prepared by limited enzymatic hydrolysis, was indistinguishable from native yolk RBP by all criteria except phosphate content [2].
• In vitro, 125I-phosvitin bound specifically to a preparation of oocyte plasma membranes as indicated by competition with unlabeled phosvitin but not with RBP [2].
• The 31P NMR spectra of egg yolk and egg white RBP are quite similar but not identical and are unaffected by the binding of riboflavin [3].
• We demonstrate that all of the phosphate of RBP is linked to serine and that most if not all of the phosphoserine residues are contained in a single tryptic peptide having a composition SerP8, Glx6, His2, Leu2, Ala, Met, Lys [3].

Biological context of LOC396449

• The sequence was identical with that of hen egg white-riboflavin binding protein except that their carboxyltermini were different, that of yolk-RBP lacked 11 or 13 amino acid residues, while hen plasma-RBP had the same C-terminal sequence as white-RBP [4].
• The complete amino acid sequence of White-RBP was determined by conventional methods [5].
• This implies that posttranslational phosphorylation of RBP is the same in liver and oviduct [3].
• The kinetics of estrogen (E) modulation of retinol-binding protein (RBP) production in the liver of immature chicks were compared with those governing de novo induction of riboflavin carrier protein (RCP) in the same tissue [6].
• To determine the phosphate binding sites in hen egg white riboflavin binding protein (RBP), a highly phosphorylated peptide, which consisted of 23 amino acid residues including eight phosphoserines, was isolated from the tryptic digest of reduced and carboxymethylated RBP [7].

Anatomical context of LOC396449

• This indicated that the C-terminal 11 or 13 amino acid residues in plasma-RBP might be cleaved off during the incorporation from the blood into the oocyte or in the yolk fluid [4].
• The carbohydrate composition of yolk-RBP was identical to that of plasma-RBP but different from that of white-RBP showing that the processing of the carbohydrate chains in the liver was different from that in the oviduct [4].
• Phosphate residues on chicken riboflavin-binding protein (RBP) have been implicated in the recognition and deposition of the protein-vitamin complex in egg yolk by the ovary [3].
• We propose that this highly anionic peptide, exposed at the surface of RBP, is the principal determinant for the uptake of RBP by the vitelline membrane of the ovarian follicle [3].
• The riboflavin binding protein (RBP) content of individual egg components were followed through the development of fertilized eggs [8].

Associations of LOC396449 with chemical compounds

• In White-RBP either six or seven of nine serine residues between Ser(185) and Ser(197) were phosphorylated [5].
• White-RBP comprised 219 amino acid residues, and the amino-terminus was pyroglutamic acid (pyrrolidonecarboxylic acid) [5].
• Likewise, cycloheximide inhibition of RBP accumulation followed a pattern similar to that of hepatic general protein synthesis [6].
• Unlike RCP induction, enhanced RBP accumulation was not strictly E dose dependent although a minimal threshold level of the steroid was required to elicit measurable response [6].
• Riboflavin-Binding Protein Exhibits Selective Sweet Suppression toward Protein Sweeteners [9].

Analytical, diagnostic and therapeutic context of LOC396449

• Although partially desialylated, dephospho-yolk RBP was identical with the native protein by several criteria, including riboflavin-binding capacity, mobility on SDS-polyacrylamide gels, and circular dichroism [2].
• PA-sugar chains of plasma-RBP were also isolated, and the structures of the PA-sugar chains of yolk- and plasma-RBPs were compared as to their elution patterns on anion-exchange chromatography and reversed-phase HPLC [10].
• The effects of pH and ionic strength on the equilibrium constants and rate constants (binding and dissociation rate constants) between riboflavin binding protein (RBP) and flavins (riboflavin, 3-carboxymethylriboflavin [CMRF], and FMN) were studied by fluorometry [11].
• Riboflavin-binding protein of hen's egg : purification & radioimmunoassay [12].
• Western blots of yolk collected from oocytes at different stages of growth show that both RBP and TTR, but not albumin, are more abundant at early stages relative to total yolk protein [13].

References