Biomaterial Database

Probing the influences of urea on the interaction of sinomenine with human serum albumin by steady-state fluorescence. 2012

Daojin Li, and Dongfeng Hong, and Han Guo, and Jianjun Chen, and Baoming Ji

College of Chemistry and Chemical Engineering, Luoyang Normal University, Luoyang 471022, China.

The binding of sinomenine to human serum albumin (HSA) in aqueous solution in the absence and presence of urea has been studied by fluorescence and the three-dimensional (3D) fluorescence at pH 7.40. Subdomain IIA binding site of human serum albumin (HSA) was characterized by examining the change in HSA fluorescence. The quenching rate constants and binding constants were calculated in the absence and presence of the denaturant. The results point to a static quenching mechanism operating in the complexes. However, the binding ability of sinomenine to denatured HSA is weaker than that of sinomenine to native HSA. Denaturation of HSA in the presence of urea is almost complete at [urea]≥ 8.0M. Upon unfolding, two fluorescence peaks were observed. One peak was assigned to the fluorescence of Trp-214 residue in a polar environment, and the other peak was assigned to the fluorescence of tyrosine residues. Compared to the free HSA, the HSA-sinomenine complex is more stable in the presence of urea.

UI	MeSH Term	Description	Entries
D008958	Models, Molecular	Models used experimentally or theoretically to study molecular shape, electronic properties, or interactions; includes analogous molecules, computer-generated graphics, and mechanical structures.	Molecular Models,Model, Molecular,Molecular Model
D009019	Morphinans	Compounds based on a partially saturated iminoethanophenanthrene, which can be described as ethylimino-bridged benzo-decahydronaphthalenes. They include some of the OPIOIDS found in PAPAVER that are used as ANALGESICS.	Morphinan
D011485	Protein Binding	The process in which substances, either endogenous or exogenous, bind to proteins, peptides, enzymes, protein precursors, or allied compounds. Specific protein-binding measures are often used as assays in diagnostic assessments.	Plasma Protein Binding Capacity,Binding, Protein
D006801	Humans	Members of the species Homo sapiens.	Homo sapiens,Man (Taxonomy),Human,Man, Modern,Modern Man
D001665	Binding Sites	The parts of a macromolecule that directly participate in its specific combination with another molecule.	Combining Site,Binding Site,Combining Sites,Site, Binding,Site, Combining,Sites, Binding,Sites, Combining
D012709	Serum Albumin	A major protein in the BLOOD. It is important in maintaining the colloidal osmotic pressure and transporting large organic molecules.	Plasma Albumin,Albumin, Serum
D013050	Spectrometry, Fluorescence	Measurement of the intensity and quality of fluorescence.	Fluorescence Spectrophotometry,Fluorescence Spectroscopy,Spectrofluorometry,Fluorescence Spectrometry,Spectrophotometry, Fluorescence,Spectroscopy, Fluorescence
D013379	Substrate Specificity	A characteristic feature of enzyme activity in relation to the kind of substrate on which the enzyme or catalytic molecule reacts.	Specificities, Substrate,Specificity, Substrate,Substrate Specificities
D014508	Urea	A compound formed in the liver from ammonia produced by the deamination of amino acids. It is the principal end product of protein catabolism and constitutes about one half of the total urinary solids.	Basodexan,Carbamide,Carmol
D017434	Protein Structure, Tertiary	The level of protein structure in which combinations of secondary protein structures (ALPHA HELICES; BETA SHEETS; loop regions, and AMINO ACID MOTIFS) pack together to form folded shapes. Disulfide bridges between cysteines in two different parts of the polypeptide chain along with other interactions between the chains play a role in the formation and stabilization of tertiary structure.	Tertiary Protein Structure,Protein Structures, Tertiary,Tertiary Protein Structures