1. Biotin in chicken egg yolk is non-covalently bound to a specific protein that comprises 0.03% of the total yolk protein (0.8 mg/yolk). This biotin-binding protein is not detectable by the normal avidin assay owing to the biotin being tightly bound. Exchange of [14C]biotin for bound biotin at 65 degrees C is the basis of an assay for this protein. 2. Biotin-binding protein from egg yolk is distinguishable from egg-white avidin on Sephadex G-100 gel filtration, although the sizes of the two proteins appear quite similar. 3. Biotin-binding protein is denatured at a lower temperature and freely exchanges biotin at lower temperatures than does avidin. 4. The biotin-binding protein in egg yolk is postulated to be responsible for the deposition of biotin in egg yolk. D-[carboxyl-14C]Biotin injected into laying hens rapidly appears in the egg bound to yolk biotin-binding protein and avidin. Over 60% of the radioactivity is eventually deposited in eggs. The kinetics of biotin deposition in the egg suggests a 25 day half-life for an intracellular biotinyl-coenzyme pool in the laying hen.
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http://dx.doi.org/10.1042/bj1570395 | DOI Listing |
J Control Release
December 2024
The State Key Laboratory of Pharmaceutical Biotechnology and Department of Neurology of Nanjing Drum Tower Hospital, School of Life Sciences and The Affiliated Hospital of Nanjing University Medical School, Nanjing University, Nanjing 210023, China; Changzhou High-Tech Research Institute of Nanjing University and Jiangsu TargetPharma Laboratories Inc, Changzhou 213164, China.
Dalton Trans
January 2025
School of Chemical Sciences, The University of Auckland, Private Bag 92019, Auckland 1142, New Zealand.
[M(arene)(HQ)Cl] complexes (M = Ru/Os/Rh/Ir; HQ = 8-hydroxyquinoline) have shown promise as anticancer agents. To assess the effect of conjugating biotin (vitamin B7) to such compounds and improve their tumor-targeting ability through interaction with the sodium-dependent multivitamin transporter (SMVT), the chlorido co-ligand was exchanged with biotinylated 6-aminoindazole. The complexes were characterized by NMR spectroscopy and mass spectrometry, and purity was determined by elemental analysis.
View Article and Find Full Text PDFChemistry
January 2025
Department of Chemistry, & Department of Bioscience & Biomedical Engineering, Indian Institute of Technology Bhilai, Durg, 491002, Chattisgarh, India.
The biotin-conjugated Fe(III) catecholate complex [Fe(BioL)], Fe(BioL) (BioLH=N-(3,4-dihydroxyphenethyl)-5-((3aS,4S,6aR)-2-oxohexahydro-1H-thieno[3,4-d]imidazol-4-yl)pentanamide) is reported as targeted magnetic resonance imaging (MRI) contrast agents (CAs) to increase the payload for early-stage imaging of tumours. The high spin state and octahedral coordination of the Fe(III) complex are confirmed by EPR spectra and DFT optimized structure, respectively. The overall formation constant (log K) of Fe(BioL) is determined as 45, which is higher than the known, more stable complex [Fe(EDTA)].
View Article and Find Full Text PDFJ Inorg Biochem
November 2024
Department of Chemistry, KU Leuven, Celestijnenlaan 200F, 3001 Leuven, Belgium. Electronic address:
The interactions of polyoxovanadates (POVs) with proteins have increasingly attracted interest in recent years due to their potential biomedical applications. This is especially the case because of their redox and catalytic properties, which make them interesting for developing artificial metalloenzymes. Organic-inorganic hybrid hexavanadates in particular offer several advantages over all-inorganic POVs.
View Article and Find Full Text PDFMethods Mol Biol
August 2024
Nancy E. and Peter C. Meinig School of Biomedical Engineering, Weill Hall, Ithaca, NY, USA.
Engineered outer membrane vesicles (OMVs) derived from Gram-negative bacteria are a promising vaccine technology for developing immunity against diverse pathogens. However, antigen display on OMVs can be challenging to control and highly variable due to bottlenecks in protein expression and localization to the bacterial host cell's outer membrane, especially for bulky and complex antigens. Here, we describe methods related to a universal vaccine technology called AvidVax (avidin-based vaccine antigen crosslinking) for rapid and simplified assembly of antigens on the exterior of OMVs during vaccine development.
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