scholarly journals Protein binding of sulfonylureas. I. Interaction of some substituted benzenesulfonyl propylureas to bovine serum albumin.

1977 ◽  
Vol 25 (12) ◽  
pp. 3405-3408 ◽  
Author(s):  
FUJIO KAMETANI ◽  
YASUKO SUMI
1979 ◽  
Vol 27 (9) ◽  
pp. 2048-2055 ◽  
Author(s):  
NAOMI I. NAKANO ◽  
TAKAYUKI OSHIO ◽  
NORIKO SATO ◽  
YOSHIMITSU SHIMAMORI ◽  
SHIGENORI YAMAGUCHI

2003 ◽  
Vol 228 (7) ◽  
pp. 850-854 ◽  
Author(s):  
Tohru Hira ◽  
Hiroshi Hara ◽  
Fusao Tomita ◽  
Yoritaka Aoyama

Dietary protein but not amino acids stimulates cholecystokinin (CCK) secretion in rat mucosal cells. However, the dietary protein sensory mechanisms and the intracellular signal pathway in the enteroendocrine cells have not yet been clarified. The relationship between dietary protein binding to cell membrane and intracellular calcium responses were examined in the CCK-producing enteroendocrine cell line STC-1. The binding of solubilized STC-1 cell membrane to proteins was analyzed using a surface plasmon resonance sensor. Intracellular calcium concentrations of STC-1 cell suspensions loaded with Fura-2 AM were measured using a spectrafluorophotometer system with continuous stirring. Intracellular calcium concentrations in STC-1 cells were increased by exposure to α-casein or casein sodium, but not to bovine serum albumin. Solubilized STC-1 membranes bound to α-casein and casein sodium but did not bind to bovine serum albumin. α-Casein demonstrated higher membrane binding and intracellular calcium stimulating activities than casein sodium. Thus, protein binding to the STC-1 cell membrane and intracellular calcium responses were correlated. Intracellular calcium responses to α-casein were suppressed by an L-type calcium channel blocker. These results suggest that casein, a dietary protein, binds to a putative receptor on the CCK-producing enteroendocrine cell membrane and elicits the subsequent intracellular calcium response via an L-type calcium channel.


2021 ◽  
Vol 12 (2) ◽  
pp. 192-196
Author(s):  
Otavio Augusto Chaves ◽  
Leonardo Vazquez

Fluoroquinolones are a family of broad spectrum, systemic antibacterial agents that have been used as therapy for infections in the respiratory and alimentary tract in animals. The pharmacodynamic of this class is widely described, predominantly to the commercial drugs ciprofloxacin (CIP), enrofloxacin (ENR), and pefloxacin (PEF). Bovine serum albumin (BSA) is the main endogenous carrier in the bovine bloodstream, being responsible for the biodistribution of different classes of molecules and drugs, including fluoroquinolones. The molecular features and interaction between BSA and fluoroquinolones are not fully described, thus, the present work enlightens the intimacy of the interaction of BSA with CIP, ENR, PEF through structural modeling and molecular docking calculation approaches. The role of key amino acid residues was assessed, indicating that the main protein binding pocket is composed by Trp-212 residue playing an important stabilization for the three fluoroquinolones through both hydrogen bonding and van der Waals forces, where reside the individual structural differences observed among the three fluoroquinolones and BSA. There is a descriptive protagonism of carboxyl group on the ENR interaction which traps the molecule and avoids the deep communication in the protein binding pocket, as well as the ligands CIP and PEF showed an interface amino acid residue interaction profile higher than 70%.


1972 ◽  
Vol 54 (3) ◽  
pp. 445-456 ◽  
Author(s):  
CHRISTINE A. MORGAN ◽  
I. D. COOKE

SUMMARY A protein-binding assay for plasma progesterone using 2% aqueous chick plasma as the binding solution is described. Details of specifications for petroleum spirit to extract the plasma are given, no chromatographic step being employed. Bound and free steroid are separated by Florisil. The system will assay plasma progesterone at a concentration of 2·0 ng/ml; other reliability data are evaluated. One technician can assay 12 duplicate plasma samples per day. The radioimmunoassay method has utilized two antisera, the first, antiprogesterone-20-0-carboxymethyl-oxime—bovine serum albumin at a dilution of 1 in 3000, the second, anti-progesterone-11-succinyl—bovine serum albumin at a dilution of 1 in 10000. Bound and free steroid are separated by dextran—charcoal suspension. The system will assay plasma progesterone at a concentration of 1·0 ng/ml. One technician can assay 24 duplicate plasma samples per day. There is a good correlation between results obtained by both competitive protein-binding (CPB) and radioimmunoassay (RIA) methods. Both methods have a place in estimating the large numbers of serial samples required in the study of physiological situations, although the RIA method will probably supersede the CPB because of its robustness and greater output.


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