scholarly journals REACTION OF ENZYMES AND PROTEINS WITH MUSTARD GAS (BIS(ß-CHLOROETHYL)SULFIDE)

1946 ◽  
Vol 30 (2) ◽  
pp. 185-210 ◽  
Author(s):  
Roger M. Herriott ◽  
M. L. Anson ◽  
John H. Northrop
Keyword(s):  
Qualitative Difference ◽  
Reaction Rates ◽  
Carboxyl Groups ◽  
Mustard Gas ◽  
Amino Groups ◽  
Rate Of Reaction ◽  
Extreme Variation ◽  
H Protein ◽  
Phenol Reagent ◽  
Yeast Hexokinase

1. The rate of reaction of mustard gas (H) with thirteen proteins has been determined. The extreme variation in reaction rates is about 100:1. 2. No qualitative difference in the results was observed when the treatment with H was carried out by the Dixon or stirring methods. 3. The kinetics have been analyzed and a bimolecular equation derived which fits the facts. 4. The carboxyl groups of all proteins reacted when the reaction with H was carried out at pH 6.0 in M/25 acetate buffer. In most cases the number of carboxyl groups covered was approximately equal to the number of H residues bound. 5. The amino groups of proteins failed to react with the possible exception of yeast hexokinase. 6. The color obtained when proteins were mixed with Folin's phenol reagent at pH 8.0 decreased as the protein was treated with H. The color returned on treatment of the H-protein with alkali and many of the combined H groups were hydrolyzed. Similar results were observed when a concentrated glycyltyrosine solution was treated with H.

scholarly journals The principle of formaldehyde, alcohol, and acetone titrations. With a discussion of the proof and implication of the zwitterion conception

1934 ◽  
Vol 115 (792) ◽  
pp. 121-141 ◽  
Keyword(s):  
Amino Acids ◽  
Carboxyl Groups ◽  
Recent Discussion ◽  
Amino Groups ◽  
Chemical Methods ◽  
Titration Method ◽  
Physico Chemical ◽  
Empirical Argument ◽  
Chemical Evidence

Consideration of the implications of the zwitterion hypothesis of Bjerrum (1923) makes it desirable to state afresh the principles underlying the methods commonly employed in the titration of amino-acids. Deductions of considerable theoretical importance, cf., e. g ., Calvery (1933) are still being made on the supposition that the alkalimetric formaldehyde titration method of Sørensen (1907) and the corresponding alcohol method of Foreman (1920) and of Willstätter and Waldschmidt-Leitz (1921) estimate the carboxyl groups of amino-acids whilst the acidimetric acetone titration of Linderstrøm-Lang (1928) estimates the amino-groups. Yet the zwitterion hypothesis indicates that this assumption is the reverse of the truth. Discussion is greatly facilitated by collective consideration of recent physico-chemical evidence clarifying the principles upon which these common bio-chemical methods rest. In a recent discussion of two of the titrimetric methods (Van Slyke and Kirk, 1933) the existence of this evidence is ignored, so that it becomes necessary to systematize and elaborate the empirical argument of these authors in the light of the relevant investigations of Grünhut (1919), Cray and Westrip (1925), Michaelis and Mizutani (1925), Birch and Harris (1930, b ), and Levy (1933). At the same time new and useful developments are indicated.

scholarly journals THE PARTIAL REACTIVATION OF FORMOLIZED TOBACCO MOSAIC VIRUS PROTEIN

1938 ◽  
Vol 22 (2) ◽  
pp. 165-191 ◽  
Author(s):  
A. Frank Ross ◽  
W. M. Stanley
Keyword(s):  
Tobacco Mosaic Virus ◽  
Mosaic Virus ◽  
Amino Nitrogen ◽  
Specific Property ◽  
Virus Protein ◽  
Amino Groups ◽  
Reactivation Process ◽  
Virus Activity ◽  
Simultaneous Decrease ◽  
Phenol Reagent

A marked reactivation of tobacco mosaic virus protein that has been partially or completely inactivated by formaldehyde was obtained by dialysis at pH 3. The activity of partially inactivated virus proteins was generally increased about 10-fold by the reactivation process. It was also found possible to reactivate completely inactive preparations to an appreciable extent. It was shown that the inactivation and the subsequent reactivation cannot be explained by the toxicity of the formaldehyde or of the formolized protein or by aggregation. Inactivation was accompanied by a decrease in amino groups as indicated by Van Slyke gasometric determinations and by colorimetric estimations using ninhydrin. Inactivation also causes a decrease in the number of groups that react with Folin's reagent at pH 7.7. The latter are probably the indole nuclei of tryptophane, for it was demonstrated that tryptophane, glycyltryptophane, and indole propionic acid react with formaldehyde in a similar manner, while tyrosine and glycyltyrosine do not. Evidence that reactivation is accompanied by an increase in amino nitrogen and in groups that react with Folin's reagent was obtained by colorimetric estimation. The demonstration that the addition of formaldehyde to the virus protein results in a simultaneous decrease of activity, of amino groups, and of groups that react with Folin's phenol reagent, and that under conditions favorable for the removal of formaldehyde the virus activity is regained and the number of such groups increases, indicates that certain of these groups play at least a partial role in the structure necessary for virus activity. These changes can best be interpreted on the basis of known chemical reactions and are considered as evidence that virus activity is a specific property of the protein.

scholarly journals Kinetics of saccharose fermentation by Kombucha

2014 ◽  
Vol 20 (3) ◽  
pp. 345-352 ◽  
Author(s):  
Eva Loncar ◽  
Katarina Kanuric ◽  
Radomir Malbasa ◽  
Mirjana Djuric ◽  
Spasenija Milanovic
Keyword(s):  
Empirical Model ◽  
Black Tea ◽  
Reaction Rates ◽  
Yeast Cells ◽  
Inoculum Concentration ◽  
Viable Cells ◽  
Rate Of Reaction ◽  
Kinetics Of ◽  
Derivatives Of ◽  
Very High

Kinetics of saccharose fermentation by Kombucha is not yet well defined due to lack of knowledge of reaction mechanisms taking place during this process. In this research kinetics of saccharose fermentation by Kombucha was analysed using the suggested empirical model. The data were obtained on 1.5 g L-1 of black tea, with 66.47 g L-1 of saccharose and using 10% (v/v) or 15% (v/v) of Kombucha. Total number of viable cells was as follows: approximately 5x105 of yeast cells per mL of the inoculum and approximately 2x106 of bacteria cells per mL of the inoculum. The samples were analysed after 0, 3, 4, 5, 6, 7 and 10 days. Their pH values and contents of saccharose, glucose, fructose, total acids and ethanol were determined. A saccharose concentration model was defined as sigmoidal function at 22oC and 30oC, and with 10% (v/v) and 15% (v/v) of inoculum quantity. Determination coefficients of the functions were very high (R2>0.99). Reaction rates were calculated as first derivatives of Boltzmann?s functions. No simple correlation between rate of reaction and independent variables (temperature and inoculum concentration) was found. Analysis of empirical model indicated that saccharose fermentation by Kombucha occurred according to very complex kinetics.

scholarly journals An Improvement in Preparation of Mortar for Radiocarbon Dating

Radiocarbon ◽  
2001 ◽  
Vol 43 (2A) ◽  
pp. 271-273 ◽  
Author(s):  
E Sonninen ◽  
H Jungner
Keyword(s):  
Grain Size ◽  
Radiocarbon Dating ◽  
Size Dependence ◽  
Reaction Rates ◽  
Error Source ◽  
Rate Of Reaction ◽  
The Matrix ◽  
The Difference

An error source in radiocarbon dating of ancient mortar is dead carbon of limestone mixed in the matrix. To eliminate the influence of limestone the difference in feasibility to react with acid between mortar and limestone is used. Since the rate of reaction depends on grain size use of a well-defined grain size can give a better separation between mortar and limestone. We present results for the grain size dependence of reaction rates for several mortar and limestone samples and discuss the application for dating.

Self-assembly of strawberry-like organic–inorganic hybrid particle clusters with directionally distributed bimetal and facile transformation of the core and corona

2020 ◽  
Vol 11 (18) ◽  
pp. 3136-3151 ◽  
Author(s):  
Shuxing Mei ◽  
Mingwang Pan ◽  
Juan Wang ◽  
Xiaopeng Zhang ◽  
Shaofeng Song ◽  
...  
Keyword(s):  
Strong Interaction ◽  
Self Assembly ◽  
Carboxyl Groups ◽  
Amino Groups ◽  
Inorganic Hybrid ◽  
Inorganic Particles ◽  
Hybrid Particle ◽  
The Core ◽  
Organic Particles ◽  
Facile Transformation

Controllable structure of organic–inorganic hybrid particle clusters were successfully fabricated by self-assembly which derived from the strong interaction between carboxyl groups of the organic particles and amino groups of the inorganic particles.

Highly selective and sensitive biosensing of dopamine based on glutathione coated silver nanoclusters enhanced fluorescence

2017 ◽  
Vol 41 (24) ◽  
pp. 15244-15250 ◽  
Author(s):  
Ramar Rajamanikandan ◽  
Malaichamy Ilanchelian
Keyword(s):  
Hydrogen Bonding ◽  
Emission Intensity ◽  
Silver Nanoclusters ◽  
Carboxyl Groups ◽  
Hydrogen Bonding Interaction ◽  
Amino Groups ◽  
Enhanced Fluorescence ◽  
Bonding Interaction

The emission intensity of red emissive GSH-AgNCs is notably enhanced after the addition of dopamine. The increasing emission intensity is attributed to the hydrogen bonding interaction between the carboxyl groups of GSH-AgNCs and amino groups of dopamine.

scholarly journals Positive Charges on Lysine Residues of the Extrinsic 18 kDa Protein Are Important to Its Electrostatic Interaction with Spinach Photosystem II Membranes

2005 ◽  
Vol 37 (11) ◽  
pp. 737-742 ◽  
Author(s):  
Jin-Peng Gao ◽  
Zhen-Hua Yong ◽  
Feng Zhang ◽  
Kang-Cheng Ruan ◽  
Chun-He Xu ◽  
...  
Keyword(s):  
Photosystem Ii ◽  
Methyl Esters ◽  
Binding Activity ◽  
Water Soluble ◽  
Carboxyl Groups ◽  
Amino Groups ◽  
Charged Amino Acids ◽  
Lysine Residues ◽  
Glycine Methyl Ester ◽  
Positively Charged

Abstract To determine the contribution of charged amino acids to binding with the photosystem II complex (PSII), the amino or carboxyl groups of the extrinsic 18 kDa protein were modified with Nsuccinimidyl propionate (NSP) or glycine methyl ester (GME) in the presence of a water-soluble carbodiimide, respectively. Based on isoelectric point shift, 4–10 and 10–14 amino groups were modified in the presence of 2 and 4 mM NSP, respectively. Similarly, 3–4 carboxyl groups were modified by reaction with 100 mM GME. Neutralization of negatively charged carboxyl groups with GME did not alter the binding activity of the extrinsic 18 kDa protein. However, the NSP-modified 18 kDa protein, in which the positively charged amino groups had been modified to uncharged methyl esters, failed to bind with the PSII membrane in the presence of the extrinsic 23 kDa protein. This defect can not be attributed to structural or conformational alterations imposed by chemical modification, as the fluorescence and circular dichroism spectra among native, GME and NSP-modified extrinsic 18 kDa proteins were similar. Thus, we have concluded that the positive charges of lysyl residues in the extrinsic 18 kDa protein are important for its interaction with PSII membranes in the presence of the extrinsic 23 kDa protein. Furthermore, it was found that the negative charges of carboxyl groups of this protein did not participate in binding with the extrinsic 23 kDa protein associated with PSII membranes.

Reduction of nitrate to ammonium by sulphate green rust: activation energy and reaction mechanism

Clay Minerals ◽  
1998 ◽  
Vol 33 (1) ◽  
pp. 87-101 ◽  
Author(s):  
H. C. B. Hansen ◽  
C. Bender Koch
Keyword(s):  
Anion Exchange ◽  
Reaction Rates ◽  
Reaction Model ◽  
Green Rust ◽  
Inorganic Nitrate ◽  
Soils And Sediments ◽  
Rate Of Reaction ◽  
Reaction Stoichiometry ◽  
Exchange Behaviour ◽  
Positively Charged

AbstractIron(II)-containing minerals are potential inorganic nitrate reductants in soils and sediments. Specifically, synthetic green rust (Fe4IIFeIII2(OH)12SO4.yH2O, GR) reduces nitrate to ammonium. The reaction of GR with two different nitrate salts, NaNO3 and Ba(NO3)2, has been compared. The reaction stoichiometry and the reaction order with respect to Fe(II) in GR does not change in the examined temperature range (15-50°C) irrespective of the nitrate salt used. Activation energies of 83.9±7.6 kJ mol-1 and 90.5±6.9 kJ mol-1 have been determined for the reaction of GR with NaNO3 and Ba(NO3)2, respectively. However, for the latter reaction the rate of reaction is increased 40 times. Based on X-ray and M6ssbauer investigations, this acceleration of the reaction rates is attributed to the forced exchange of sulphate with nitrate in GR interlayers caused by precipitation of BaSO4 outside the GR particles, a reaction which does not occur in the presence of NaNO3. This difference in anion exchange behaviour is confirmed by anion exchange experiments with the redox-inactive GR-analogue, pyroaurite. A reaction model initiated by nitrate electrostatically bound at positively charged sites of GR is proposed.

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