scholarly journals o-Quinones formed in plant extracts. Their reaction with bovine serum albumin

1969 ◽  
Vol 112 (5) ◽  
pp. 619-629 ◽  
Author(s):  
W. S. Pierpoint
Keyword(s):  
Bovine Serum Albumin ◽  
Serum Albumin ◽  
Plant Extracts ◽  
Bovine Serum ◽  
Succinic Anhydride ◽  
Thiol Group ◽  
Excess Oxygen ◽  
Amino Group ◽  
Amino Groups ◽  
Ellman's Reagent

1. The reactions between chlorogenoquinone, the o-quinone formed during the oxidation of chlorogenic acid, and bovine serum albumin depend on the ratio of reactants. 2. When the serum albumin is in excess, oxygen is not absorbed and the products are colourless. This reaction probably involves the thiol group of bovine serum albumin; it does not occur with bovine serum albumin which has been treated with p-chloromercuribenzoate, iodoacetamide or Ellman's reagent. 3. When bovine serum albumin reacts with excess of chlorogenoquinone, oxygen is absorbed and the products are red. The red colour is probably formed by reaction of the lysine ∈-amino groups of bovine serum albumin, as it is prevented by treating the protein with formaldehyde, succinic anhydride or O-methylisourea. 4. Bovine serum albumin modified by a 1·5-fold (BSA-Q) and a fivefold (BSA-Q2) excess of chlorogenoquinone were separated by chromatography on DEAE-Sephadex A-50, and some of their properties observed. 5. Reaction of BSA-Q2 with fluorodinitrobenzene suggests that the terminal α-amino group, as well as lysine ∈-amino groups, are combined with chlorogenoquinone.

Sorption of Substituted Phenylamides onto Bovine Serum Albumin

Weed Science ◽  
1971 ◽  
Vol 19 (3) ◽  
pp. 269-273 ◽  
Author(s):  
N. D. Camper ◽  
D. E. Moreland
Keyword(s):  
Bovine Serum Albumin ◽  
Serum Albumin ◽  
Bovine Serum ◽  
Phenyl Ring ◽  
Protein Modification ◽  
Carbonyl Oxygen ◽  
Amide Hydrogen ◽  
Amino Groups ◽  
Influence Of Ph ◽  
Derivatives Of

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.

New Method for the Determination of Free Amino Groups in Intact Pure Proteins: Relationship to Available Lysine

1976 ◽  
Vol 59 (6) ◽  
pp. 1251-1254
Author(s):  
James M Purcell ◽  
Daniel J Quimby ◽  
James R Cavanaugh
Keyword(s):  
Bovine Serum Albumin ◽  
Bovine Serum ◽  
Free Amino ◽  
Amino Group ◽  
Amino Groups ◽  
Primary Amino ◽  
Available Lysine ◽  
Β Lactoglobulin ◽  
Group Concentration

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.

scholarly journals o-Quinones formed in plant extracts. Their reactions with amino acids and peptides

1969 ◽  
Vol 112 (5) ◽  
pp. 609-616 ◽  
Author(s):  
W. S. Pierpoint
Keyword(s):  
Amino Acids ◽  
Amino Acid ◽  
Plant Extracts ◽  
Thiol Group ◽  
Amino Group ◽  
Amino Groups ◽  
Terminal Amino Acid ◽  
Secondary Reactions ◽  
Terminal Amino ◽  
Group 5

1. The reactions of amino acids and peptides with the o-quinones produced by the enzymic oxidation of chlorogenic acid and caffeic acid have been studied manometrically and spectrophotometrically. 2. Amino acids, except lysine and cysteine, react primarily through their α-amino groups to give red or brown products. These reactions, which compete with the polymerization of the quinones, are followed by secondary reactions that may absorb oxygen and give products with other colours. 3. The ∈-amino group of lysine reacts with the o-quinones in a similar way. The thiol group of cysteine reacts with the quinones, without absorbing oxygen, giving colourless products. 4. Peptides containing cysteine react with the o-quinones through their thiol group. 5. Other peptides, such as glycyl-leucine and leucylglycine, react primarily through their α-amino group and the overall reaction resembles that of the N-terminal amino acid except that it is quicker. 6. With some peptides, the secondary reactions differ from those that occur between the o-quinones and the N-terminal amino acids. The colours produced from carnosine resemble those produced from histidine rather than those from β-alanine, and the reactions of prolylalanine with o-quinones are more complex than those of proline.

Sensitive Enzyme Immunoassay of Cephalexin Residues in Milk, Hen Tissues, and Eggs

1988 ◽  
Vol 71 (5) ◽  
pp. 915-920
Author(s):  
Tsunehiro Kitagawa ◽  
Yukio Gotoh ◽  
Kazuyo Uchihara ◽  
Youko Kohri ◽  
Tihoko Kinoue ◽  
...  
Keyword(s):  
Bovine Serum Albumin ◽  
Serum Albumin ◽  
Enzyme Immunoassay ◽  
Bovine Serum ◽  
Limit Of Detection ◽  
Rabbit Antiserum ◽  
Egg Yolk ◽  
Amino Group ◽  
Thiol Groups ◽  
Cross Linker

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.

scholarly journals Characterization of bovine serum albumin glycated with glucose, galactose and lactose.

2008 ◽  
Vol 55 (3) ◽  
pp. 491-497 ◽  
Author(s):  
Ana Irene Ledesma-Osuna ◽  
Gabriela Ramos-Clamont ◽  
Luz Vázquez-Moreno
Keyword(s):  
Bovine Serum Albumin ◽  
Serum Albumin ◽  
Bovine Serum ◽  
Lectin Binding ◽  
Enzymatic Reaction ◽  
Biological Research ◽  
Binding Assays ◽  
Amino Groups ◽  
Sds Page ◽  
Biological Recognition

The non-enzymatic reaction between reducing sugars and proteins, known as glycation, has received increased attention from nutritional and medical research. In addition, there is a large interest in obtaining glycoconjugates of pure well-characterized oligosaccharides for biological research. In this study, glycation of bovine serum albumin (BSA) by d-glucose, d-galactose and d-lactose under dry-heat at 60 degrees C for 30, 60, 120, 180 or 240 min was assessed and the glycated products studied in order to establish their biological recognition by lectins. BSA glycation was monitored using gel electrophoresis, determination of available amino groups and lectin binding assays. The BSA molecular mass increase and glycation sites were investigated by mass spectrometry and through digestion with trypsin and chymotrypsin. Depending on time and type of sugar, differences in BSA conjugation were achieved. Modified BSA revealed reduction of amino groups' availability and slower migration through SDS/PAGE. d-galactose was more reactive than d-glucose or d-lactose, leading to the coupling of 10, 3 and 1 sugar residues, respectively, after 120 minutes of reaction. BSA lysines (K) were the preferred modified amino acids; both K256 and K420 appeared the most available for conjugation. Only BSA-lactose showed biological recognition by specific lectins.

Conjugation of N-acylated amino sugars to protein by reductive alkylation using sodium cyanoborohydride: application to an azo derivative of α-amanitin

1991 ◽  
Vol 69 (7) ◽  
pp. 418-427 ◽  
Author(s):  
Jerald E. Mullersman ◽  
James F. Preston III
Keyword(s):  
Bovine Serum Albumin ◽  
Serum Albumin ◽  
Bovine Serum ◽  
Protein Modification ◽  
Reductive Coupling ◽  
Reductive Alkylation ◽  
Amino Groups ◽  
Protein Polymerization ◽  
Calf Thymus ◽  
Aldehyde Groups

Reductive alkylation mediated by cyanoborohydride is an attractive approach to the conjugation of small molecules, such as drugs, to proteins. This reaction is specific for protein amino groups and can be conducted under mild conditions with little risk of protein polymerization. However, the lability of the aldehyde function that is needed in such reactions presents a difficulty. We have investigated the use of derivatives of D-galactosamine and D-glucosamine in reductive alkylation, since these sugars contain aldehyde groups that are inherently protected and that may be readily linked to other molecules through their amino groups. The amino groups of these sugars were acylated with N-4-nitrobenzoylglycylglycine. Studies of the reductive coupling of the resultant adducts to bovine serum albumin revealed that conjugation to albumin is strongly dependent on cyanoborohydride, is much faster in the presence of borate, and shows a marked increase in rate between pH 7.0 and 9.0. In the presence of borate, the glucosamine derivative coupled much more rapidly than did the galactosamine derivative. The aryl nitro group of the glucosamine adduct was selectively reduced to an amine, diazotized, and reacted with α-amanitin to form an azo compound. This azo derivative was reductively coupled to form conjugates that inhibit calf thymus RNA polymerase II.Key words: α-amanitin, borate, bovine serum albumin, cyanoborohydride, protein modification, reductive alkylation.

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