scholarly journals The reaction of 2,4,6-trinitrobenzenesulphonic acid with amino acids, peptides and proteins

1968 ◽  
Vol 108 (3) ◽  
pp. 383-391 ◽  
Author(s):  
R. B. Freedman ◽  
G. K. Radda
Keyword(s):  
Amino Acids ◽  
Glutamate Dehydrogenase ◽  
Free Amino ◽  
Reactive Species ◽  
Second Order ◽  
Amino Group ◽  
Exponential Rate ◽  
Amino Groups ◽  
Sh Group ◽  
Kinetics Of

1. The kinetics of the reaction of 2,4,6-trinitrobenzenesulphonic acid with various amino acids, peptides and proteins were studied by spectrophotometry. 2. The reaction of the α- and ∈-amino groups in simple amino acids was found to be second-order, and the unprotonated amino group was shown to be the reactive species. 3. By allowing for the concentration of unreactive −NH3+ group, intrinsic reactivities for the free amino groups were derived and shown to be correlated with the basicities. 4. The SH group of N-acetylcysteine was found to be more reactive to 2,4,6-trinitrobenzenesulphonic acid than most amino groups. 5. The reactions of insulin, chymotrypsinogen and ribonuclease with 2,4,6-trinitrobenzenesulphonic acid were analysed in terms of three exponential rate curves, each referring to one or more amino groups of the proteins. 6. The reaction of lysozyme with 2,4,6-trinitrobenzenesulphonic acid was found to display an acceleration effect. 7. From the reaction of 2,4,6-trinitrobenzenesulphonic acid with glutamate dehydrogenase at several enzyme concentrations, it was possible to discern two sets of amino groups of different reactivity, and to show that the number of groups in each set was decreased by aggregation of the enzyme.

Kinetics and mechanism of oxidation of DL-α-alanine by permanganate ion in acid perchlorate media

1991 ◽  
Vol 69 (12) ◽  
pp. 2018-2023 ◽  
Author(s):  
Refat M. Hassan
Keyword(s):  
Amino Acids ◽  
Ionic Strength ◽  
Acid Solution ◽  
Second Order ◽  
Perchloric Acid Solution ◽  
Oxidation Reduction ◽  
Initial Stage ◽  
Aqueous Perchloric Acid ◽  
Mechanism Of Oxidation ◽  
Kinetics Of

The kinetics of permanganate oxidation of DL-α-alanine in aqueous perchloric acid solution at a constant ionic strength of 2.0 mol dm−3 has been investigated spectrophotometrically. The reaction was found to show second-order kinetics overall with respect to each of the reactants in the slow initial stage; the second-order kinetics are not, however, maintained throughout the relatively fast final stage of reaction. The added salts lead to the prediction that Mn(III) and (or) Mn(IV) play a very important role in the reaction kinetics. A tentative mechanism consistent with the kinetics is discussed. Key words: kinetics, oxidation, reduction, amino acids, permanganate.

Effects of abomasal infusions of sodium caseinate, a hydrolysate of casein or a corresponding mixture of free amino acids on milk yield and composition in dairy cows

1995 ◽  
Vol 62 (1) ◽  
pp. 29-37 ◽  
Author(s):  
Jai-Jun Choung ◽  
David G. Chamberlain
Keyword(s):  
Amino Acids ◽  
Dairy Cows ◽  
Free Amino Acids ◽  
Free Amino ◽  
Milk Protein ◽  
Bioactive Peptides ◽  
Basal Diet ◽  
Sodium Caseinate ◽  
Amino Acid Residues ◽  
Kinetics Of

SummaryThe effects of the form in which amino acids are presented to the abomasum on the milk production of dairy cows receiving a basal diet of grass silage and a barley-based supplement were examined in two experiments. Effects of abomasal infusions of sodium caseinate were compared with the effects of corresponding levels of either an enzymic hydrolysate of casein (Expt 1) or a corresponding mixture of free amino acids (FAA; Expt 2). In Expt 1, although the yield of protein in milk increased progressively with each level of infusion, the yields of protein were greater for the caseinate than for the hydrolysate. Again, in Expt 2, for milk protein yield, sodium caseinate was superior to FAA at the lower level of infusion. In both experiments, the hydrolysate and FAA treatments were associated with higher concentrations of fat in the milk. There were indications of differences in the pattern of secretion of glucagon between the caseinate and FAA treatments. It is concluded that the differences between treatments relate either to the kinetics of absorption of amino acid residues or to the action of bioactive peptides released during digestion of casein.

Automated Determination of Free Amino Groups in Serum and Plasma Using 2,4,6-Trinitrobenzene Sulfonate

1969 ◽  
Vol 15 (9) ◽  
pp. 891-901 ◽  
Author(s):  
D W Palmer ◽  
T Peters
Keyword(s):  
Amino Acids ◽  
Free Amino Acids ◽  
Free Amino ◽  
Clinical Applications ◽  
Amino Groups ◽  
Automated Method ◽  
Total Free Amino Acids ◽  
Colored Complexes ◽  
Automated Determination

Abstract A simple automated method is described for determining the level of total free amino acids in the blood. The method utilizes the AutoAnalyzer, and is based on the formation of colored complexes by uniting free amino groups with 2,4,6-trinitrobenzene sulfonate (TNBS). Proteins do not interfere because the free amino acids are first separated by dialysis. Characteristics of the reaction and potential clinical applications of the procedure are discussed.

Condensation de la poly-L-lysine et de la poly- L-ornithine avec des dérivés de bases puriques et de sulfamides

1969 ◽  
Vol 47 (19) ◽  
pp. 3641-3646 ◽  
Author(s):  
Louis Berlinguet ◽  
Jacky Gautier
Keyword(s):  
Aqueous Solution ◽  
Amino Acids ◽  
Free Amino ◽  
Sulfonyl Chloride ◽  
Amino Groups ◽  
Carbodiimide Method

Free ε-amino groups of poly-L-lysine and poly-L-ornithine were alkylated in aqueous solution with 6-chloropurine and 6-chloropurine-riboside, were acylated with 4-acetylamino benzene sulfonyl chloride, and were condensed with N-(4-acetylamino benzene sulfonyl)-glycine using carbodiimide method. Approximately 50% of the free amino groups of the basic polypetides were substituted. The same method was used to prepare poly-α-amino acids bearing radioactive substituants.

Effect of cross-linking agents on insulin associated responses in adipocytes

1982 ◽  
Vol 60 (10) ◽  
pp. 987-1000 ◽  
Author(s):  
H. Joseph Goren ◽  
C. Ronald Kahn
Keyword(s):  
Insulin Receptor ◽  
Glucose Transport ◽  
Free Amino ◽  
Glucose Oxidation ◽  
Insulin Binding ◽  
Cross Linking ◽  
Amino Group ◽  
Amino Groups ◽  
Disuccinimidyl Suberate ◽  
Reactive Groups

The effect of 10 bifunctional cross-linking agents and four monofunctional analogues was studied on isolated adipocytes. [125I]Insulin binding and degradation, basal and insulin-stimulated glucose oxidation, and 3-O-methyl glucose uptake were measured. Two cross-linkers, which possess succinimide ester residues (disuccinimidyl suberate and dithiobis(succinimidyl propionate)) and react selectively with amino groups, appeared to react relatively specifically with the insulin receptor. Both produced a slight stimulation of basal glucose transport and metabolism, a marked inhibition of insulin-stimulated glucose transport and metabolism, and a marked decrease in insulin binding. Pretreatment of cells with unlabelled insulin partially blocked the effect of disuccinimidyl suberate, and as has been previously shown, disuccinimidyl suberate cross-linked insulin to its receptor. A monofunctional analogue of these compounds was 100-fold less active in altering cellular metabolic activity. Bisimidates, such as dimethyl suberimidate, dimethyl adipimidate, and dimethyl dithiobispropionimidate, also react with free amino groups but are more hydrophilic. These agents produced similar effects on glucose oxidation as the succinimide esters, but had little or no effect on insulin binding. The effects of these agents are not blocked by insulin and they do not cross-link insulin to its receptor. Mixed bifunctional reagents containing either a succinimide ester or an imidate and a group which reacts with thiols produced effects similar to the cross-linkers containing two succinimide groups or bisimidates, respectively. The bifunctional arylating agents difluorodinitrobenzene and bis(fluoronitrophenyl)sulfone produce marked effects on insulin binding and glucose oxidation at micromolar concentrations, but the monofunctional analogue fluorodinitrobenzene is almost equally active suggesting that with these compounds chemical modifications and not cross-linking was important. With neither the mixed bifunctional reagents, nor the arylating agents, did insulin pretreatment alter the effect of cross-linker and none of these agents cross-linked [125I]insulin to its receptor. These data suggest that the insulin receptor possesses a free amino group in a hydrophobic environment in its active site. A reactive amino group in a hydrophilic environment as well as other reactive groups are also present in some component of the insulin receptor–effector complex. Chemical modification or cross-linking of these functional groups results in an inhibition or mimicking of insulin action. Further study will be required to identify the exact locus of these sites.

scholarly journals Amino-functionalized (meth)acryl polymers by use of a solvent-polarity sensitive protecting group (Br-t-BOC)

2016 ◽  
Vol 12 ◽  
pp. 245-252
Author(s):  
Helmut Ritter ◽  
Monir Tabatabai ◽  
Markus Herrmann
Keyword(s):  
Free Radical ◽  
Nmr Spectroscopy ◽  
Free Amino ◽  
Solvent Polarity ◽  
Protecting Group ◽  
Amino Groups ◽  
Neighboring Group ◽  
H Nmr ◽  
Polarity Sensitive ◽  
Kinetics Of

We describe the synthesis of bromo-tert-butyloxycarbonyl (Br-t-BOC)-amino-protected monomers 2-((1-bromo-2-methylpropan-2-yl)oxycarbonylamino)ethyl (meth)acrylate 3a,b. For this purpose, 2-isocyanatoethyl (meth)acrylate 1a,b was reacted with 1-bromo-2-methylpropan-2-ol (2a). The free radical polymerization of (Br-t-BOC)-aminoethyl (meth)acrylates 3a,b yielded poly((Br-t-BOC)-aminoethyl (meth)acrylate) 6a,b bearing protected amino side groups. The subsequent solvolysis of the Br-t-BOC function led to the new polymers poly(2-aminoethyl (meth)acrylate) 8a,b with protonated free amino groups. The monomers and the resulting polymers were thoroughly characterized by 1H NMR, IR, GPC and DSC methods. The kinetics of the deprotection step was followed by 1H NMR spectroscopy. The solvent polarity and neighboring group effects on the kinetics of deprotection are discussed.

scholarly journals Spectrophotometric measurement of the liberation of the α-amino group of cysteine residues in polypeptides

1966 ◽  
Vol 100 (2) ◽  
pp. 309-314 ◽  
Author(s):  
S Streichman ◽  
Y Avi-Dor
Keyword(s):  
Spectral Characteristics ◽  
Cysteine Residues ◽  
Amino Group ◽  
Peptide Bonds ◽  
Spectral Changes ◽  
Sh Group ◽  
Induced Changes ◽  
Kinetics Of ◽  
Hydrolysis Of ◽  
Specific Peptide

1. The reaction between beta-bromopyruvic acid and SH groups of cysteine residues in reduced ribonuclease and in some other polypeptides was investigated. 2. One molecule of the acid was found to be necessary to block one SH group in reduced ribonuclease. The stoicheiometry of the interaction and the spectral characteristics of the compound formed suggested that the product is and S-oxalomethyl (R.S.CH(2).CO.CO(2)H) derivative of reduced ribonuclease. 3. Digestion of reduced S-oxalomethylated ribonuclease by trypsin or chymotrypsin induced changes in the spectrum that could be attributed to the liberation of the alpha-amino group of S-oxalomethylated cysteine residues from peptide bonds. The spectral changes that accompanied the hydrolysis of specific peptide bonds in reduced S-oxalomethylated ribonuclease and S-oxalomethylated co-poly(l-Lys,l-CySH) allowed the kinetics of the digestion to be followed. 4. Possible applications of the spectrophotometric method in the study of protein structure are discussed.

Sign in / Sign up

Export Citation Format

Share Document