The Influence of Amino Group Position on Aryl Moiety of SarAr on Metal Complexation and Protein Labelling

2016 ◽  
Vol 69 (9) ◽  
pp. 1054 ◽  
Author(s):  
Vincent Jamier ◽  
Eskender Mume ◽  
Cyril Papamicaël ◽  
Suzanne. V. Smith

New hexaazamacrobicyclic cage bi-functional chelators (BFCs), 1-N-(3-aminobenzyl)-3,6,10,13,16,19-hexaazabicyclo[6.6.6]eicosane-1,8-diamine (m-SarAr) and 1-N-(2-aminobenzyl)-3,6,10,13,16,19-hexaazabicyclo[6.6.6]eicosane-1,8-diamine (o-SarAr), were synthesised. Their complexation with selected transitions metal ions i.e. CuII, CoII, and CdII was investigated over a range of pH at micromolar concentrations. CuII was complexed by m-SarAr and o-SarAr rapidly within 5 min in pH range of 5–9 at ambient temperature. In contrast, the complexation of CoII and CdII by these ligands was slower. The conjugation efficiencies of p-SarAr, m-SarAr, and o-SarAr to bovine serum albumin (BSA) were compared under various reactions. Conditions were optimised to a molar ratio of BSA/N-(3-dimethylaminopropyl)-N′-ethylcarbodiimide (EDC)/BFC of 1 : 250 : 50 in pH 5 buffer for 30 min at ambient temperature. Under these conditions, the average number of p-SarAr, m-SarAr, or o-SarAr attached to BSA were determined to be 2.21 ± 0.16, 4.90 × 10–1 ± 2.48 × 10–2, and 2.67 × 10–2 ± 2.67 × 10–3, respectively. This fundamental study clearly demonstrates that the position of the amine on the phenyl ring has a significant effect on the metal complexation and conjugation reactions with BSA.

1974 ◽  
Vol 52 (3) ◽  
pp. 196-202 ◽  
Author(s):  
Lee J. Grota ◽  
Gregory M. Brown

Serotonin, N-acetyl serotonin, and 5-methoxy-N-acetyl serotonin (melatonin) were conjugated to bovine serum albumin (BSA) using formaldehyde. The molar ratio of hapten to protein was determined spectrophotometrically. Spectrophotometric data indicated that serotonin and N-acetyl serotonin but not melatonin were conjugated to bovine serum albumin. Selected hapten–protein conjugates were suspended in Freund's adjuvant and injected into rabbits. Antisera were harvested monthly and screened by double immunodiffusion. Immunodiffusion and inhibition tests indicated that antibodies raised to serotonin–BSA reacted with serotonin and 5-methoxytryptamine but failed to cross react with N-acetyl serotonin or melatonin. Inhibition tests indicated that antibodies to N-acetyl serotonin – BSA reacted with N-acetyl serotonin and cross reacted with melatonin but not with serotonin or 5-methoxytryptamine.


1971 ◽  
Vol 49 (12) ◽  
pp. 1267-1275 ◽  
Author(s):  
D. E. Goldsack ◽  
P. M. Waern

Pressure jump kinetic studies of the conformational change occurring in bovine serum albumin in neutral solutions have been carried out over the pH range 6.5–9.5. Two distinct relaxation effects are observed at each pH. The faster relaxation is attributed to binding of the dye to the protein, and the slower relaxation is related to the conformational change occurring in the protein. This slower relaxation effect is pH dependent with a maximum value near pH 8. Detailed analysis of these data leads to a mechanism for the conformational change which indicates that the one form of the protein has an ionizable group with a pK of 8.7 which changes to a pK of 6.7 when the protein undergoes the conformational change. A simple iterative procedure is given for analyzing the pH dependence of a relaxation time constant for a cyclic mechanism involving only one ionizing group controlling the conformational change.


1986 ◽  
Vol 236 (1) ◽  
pp. 307-310 ◽  
Author(s):  
M Y Khan

The domain III of bovine serum albumin containing residues 377-582 of the protein sequence was isolated and its behaviour in acid solution was studied. The fragment was found to undergo structural transformations over the pH range 3.5-4.5 known to cause N-F transition in serum albumin. On the other hand, an albumin fragment that was devoid of domain III was unable to exhibit such a transition. These results were consistent with a mechanism where N-F transition involves the separation of domain III from the rest of the albumin starts at about pH 4.3 and is completed at pH 3.5.


Weed Science ◽  
1971 ◽  
Vol 19 (3) ◽  
pp. 269-273 ◽  
Author(s):  
N. D. Camper ◽  
D. E. Moreland

The influence of pH, temperature, ionic strength, and protein modification on the sorption (moles of chemical bound per mole of protein) of 3-(3,4-dichlorophenyl)-1,1-dimethylurea (diuron) and 3′,4′-dichloropropionanilide (propanil) to bovine serum albumin (hereinafter referred to as BSA) was examined. Free amino groups of BSA were involved in the binding of both diuron and propanil. In addition, tryptophanyl residues appeared to be involved in the binding of propanil. Studies made with derivatives of diuron suggested that the amide hydrogen and carbonyl oxygen of the phenylamide are involved in the binding mechanism. Conformation of the protein was suggested to control the extent of binding. Increased chlorination of the phenyl ring was correlated with increased binding onto BSA. Propanil was bound to a greater extent than diuron by the protein.


Materials ◽  
2019 ◽  
Vol 12 (7) ◽  
pp. 1022 ◽  
Author(s):  
Jing Yu ◽  
Yun Chen ◽  
Liqun Xiong ◽  
Xiaoyue Zhang ◽  
Yue Zheng

Proteins, due to their binding selectivity, are promising candidates for fabricating nanoscale bio-sensors. However, the influence of structural change on protein conductance caused by specific protein-ligand interactions and disease-induced degeneration still remains unknown. Here, we excavated the relationship between circular dichroism (CD) spectroscopy and conductive atomic force microscopy (CAFM) to reveal the effect of the protein secondary structures changes on conductance. The secondary structure of bovine serum albumin (BSA) was altered by the binding of drugs, like amoxicillin (Amox), cephalexin (Cefa), and azithromycin (Azit). The CD spectroscopy shows that the α-helical and β-sheet content of BSA, which varied according to the molar ratio between the drug and BSA, changed by up to 6%. The conductance of BSA monolayers in varying drug concentrations was further characterized via CAFM. We found that BSA conductance has a monotonic relation with α-helical content. Moreover, BSA conductance seems to be in connection with the binding ability of drugs and proteins. This work elucidates that protein conductance variations caused by secondary structure transitions are triggered by drug-binding and indicate that electrical methods are of potential application in protein secondary structure analysis.


1976 ◽  
Vol 59 (6) ◽  
pp. 1251-1254
Author(s):  
James M Purcell ◽  
Daniel J Quimby ◽  
James R Cavanaugh

Abstract A new rapid method for the quantitative and routine determination of free amino groups in intact pure proteins has been developed. Primary amino groups are labeled with fluorescamine and the labeled groups are detected by absorption spectroscopy in the range 375–390 nm. The amino group concentration can be determined in a few minutes without hydrolyzing the labeled protein and extracting a lysine derivative. The method was tested with the following proteins: lysozyme, α-lactalbumin, β-lactoglobulin, bovine serum albumin, ribonuclease, ribonuclease-S-peptide, and αsl-rasciii B. Application of this method to the estimation of available lysine is discussed.


1975 ◽  
Vol 42 (2) ◽  
pp. 267-275 ◽  
Author(s):  
J. G. Zadow ◽  
R. D. Hill

SummaryCarboxymethyl cellulose (CMC) formed insoluble complexes with β-lactoglobulin, bovine serum albumin and Na caseinate. Maximum precipitation of the β-lactoglobulin-CMC complex occurred at pH 3·2, whereas maximum precipitation of the bovine serum albumin-CMC complex and the Na caseinate-CMC complex occurred at pH 2·8. The ratio of CMC to protein for maximum precipitation depended on the protein, being greatest for Na caseinate and least for bovine serum albumin. The percentage of protein precipitated by CMC decreased with increasing ionic strength of the solution, the rate of decrease being least for bovine serum albumin. At a given ionic strength, more protein was precipitated by CMC of high degree of substitution than by CMC of low degree of substitution. The change in pH (ΔpH) occurring on mixing CMC and unbuffered protein solutions, each initially at the same pH, was measured. ΔpH was negative for β-lactoglobulin-CMC mixtures over the pH range 7–2 (minimum at pH 5·5). For bovine serum albumin-CMC and Na caseinate-CMC mixtures, ΔpH was positive between pH 7 and 3·2 (maximum at pH 4·5), zero at pH 3·2 and negative between pH 3·2 and 2·0 (minimum at pH 2·8).


1982 ◽  
Vol 203 (3) ◽  
pp. 735-742 ◽  
Author(s):  
Bruno Venerando ◽  
Benvenuto Cestaro ◽  
Amelia Fiorilli ◽  
Riccardo Ghidoni ◽  
Augusto Preti ◽  
...  

Gd1a, Gd1b and Gt1b gangliosides were dispersed in the following membrane-mimicking systems: (a) homogeneous micelles; (b) mixed micelles with Gm1 ganglioside (which is resistant to the enzyme action), Triton X-100 or bovine serum albumin; (c) small unilamellar vesicles of egg phosphatidylcholine. The effect of dispersion on sialic acid release by Vibrio cholerae sialidase was studied. As reference substrates freely interacting with the enzyme the lipid-free carbohydrates of Gd1a and 3′-sialosyl-lactose were employed. The apparent Vmax. of the enzyme was, with all the gangliosides, dependent on the type of ganglioside dispersion. It was lowest for homogeneous micelles and mixed micelles with ganglioside Gm1, and increased about 6-fold for ganglioside/bovine serum albumin lipoprotein micelles, 15-fold for mixed-ganglioside/Triton X-100 micelles (optimal molar ratio 1:7.5) and 30-fold for phosphatidylcholine vesicles containing 2.5 mol% ganglioside (this proportion was optimal for enzyme activity on the vesicles). For ganglioside Gd1a, the activity on Triton X-100 mixed micelles and on mixed vesicles was even greater (3- and 6-fold respectively) than that displayed on Gd1a lipid-free carbohydrate. With each of the used gangliosides the apparent Km values were very similar values for homogeneous micelles and vesicular dispersions, but showed marked increases for Triton X-100 mixed micelles, approaching the values exhibited by reference oligosaccharides. Triton X-100 micelles and phosphatidylcholine vesicles did not appreciably alter the kinetics of sialidase action on 3′-sialosyl-lactose and on Gd1a lipid-free carbohydrate, indicating that the above effects are dependent on the intrinsic characteristics of the membrane-like systems containing gangliosides.


1993 ◽  
Vol 58 (11) ◽  
pp. 2682-2694 ◽  
Author(s):  
Kateřina Čermáková ◽  
Ondřej Šesták ◽  
Pavel Matějka ◽  
Vladimír Baumruk ◽  
Blanka Vlčková

Formation of Ag colloid/adsorbate SERS-active systems (upon adsorption of the selected adsorbates on the surface of Ag colloidal particles) as a function of (i) NaBH4 to AgNO3 molar ratio in the preparation protocol of Ag colloid, and (ii) aging of the colloid has been investigated by Surface-enhanced Raman scattering (SERS) spectroscopy. Oligomeric synthetic polypeptides, bovine serum albumin, phosphate coadsorbed with CuTMePyP [copper(II) derivative of 5,10,15,20-tetrakis-(N-methylpyridinium-4-yl)porphyrin chloride] and borates in systems with N-containing bases were selected as model adsorbates. Both (i) a decrease of NaBH4 to AgNO3 molar ratio upon preparation and (ii) aging of Ag colloid affect adsorption of the adsorbates and consequently, their SERS spectra, in the same manner. Aging of Ag colloid is thus viewed as a slow hydrolysis of BH4- anions. The actual concentration of BH4- in the system is identified as the most important factor controlling adsorption of all the selected adsorbates on the surface of Ag colloid. As this factor can be related to the surface potential, the conditions controlling adsorption of the selected adsorbates are specified in terms of a more negative and/or more positive surface potential of Ag colloidal particles. A more positive surface potential promotes adsorption of polypeptides, bovine serum albumin and phosphate while observation of spectral features of borates in the SERS spectra of N-containing bases in alkaline solutions is conditioned by a more negative surface potential.


1988 ◽  
Vol 71 (5) ◽  
pp. 915-920
Author(s):  
Tsunehiro Kitagawa ◽  
Yukio Gotoh ◽  
Kazuyo Uchihara ◽  
Youko Kohri ◽  
Tihoko Kinoue ◽  
...  

Abstract A sensitive enzyme immunoassay for cephalexin (CEX) was developed using the rabbit antiserum to CEX, Β-D-galactosidase-labeled CEX, and a double-antibody separation method. The immunogen of CEX was prepared by coupling the amino group of CEX to thiol groups introduced into bovine serum albumin by the use of N-(mmaleimidobenzoyloxy) succinimide as a cross-linker. Highly titered antiserum to CEX was produced in rabbits immunized with the immunogen. Enzyme labeling of CEX with Β-D-galactosidase was done by using 7V-(gamma-maleimidobutyryloxy)succinimide as the crosslinker. The limit of detection was 30 ng CEX/mL sample solution. Application of the method to CEX drug residues detected 30 ng/mL in milk, 60 ng/g in egg yolk, and 400 ng/g in hen tissue.


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