scholarly journals A spectrophotometric method for the microdetermination of periodate

1968 ◽  
Vol 108 (5) ◽  
pp. 883-887 ◽  
Author(s):  
Robert Fields ◽  
H. B. F. Dixon
Keyword(s):  
Methyl Ester ◽  
Spectrophotometric Method ◽  
Ribonuclease A ◽  
Sample Solution ◽  
S Protein

1. A method is described for measuring the concentration of periodate over the range 0·2–20μm by adding 1,2-di-(p-dimethylaminophenyl)ethane-1,2-diol to a sample solution. Periodate cleaves this compound to from two molecules of p-dimethylaminobenzaldehyde, the extinction of which is then read at 352mμ. 2. The method has been used to follow the course of periodate oxidations of serine methyl ester, ribonuclease A and ribonuclease S-protein. Addition of the reagent stops further periodate reaction by reducing the remaining periodate to iodate. 3. The presence of protein does not interfere with the assay.

scholarly journals Structure and enzymic activity of ribonuclease-A esterified at glutamic acid-49 and aspartic acid-53

1978 ◽  
Vol 173 (3) ◽  
pp. 821-830 ◽  
Author(s):  
A. Seetharama Acharya ◽  
Belur N. Manjula ◽  
Paul J. Vithayathil
Keyword(s):  
Methyl Ester ◽  
Glutamic Acid ◽  
Aspartic Acid ◽  
Spectral Characteristics ◽  
Dimethyl Ester ◽  
Limited Proteolysis ◽  
Ribonuclease A ◽  
Enzymic Activity ◽  
S Protein ◽  
Hydrolysis Of

The dimethyl ester of bovine pancreatic ribonuclease-A (dimethyl RNAase-A), the initial product of esterification of RNAase-A in anhydrous methanolic HCl, was isolated in a homogeneous form. The two carboxy functions esterified in this derivative are those of glutamic acid-49 and aspartic acid-53. There were no changes in the u.v.-absorption spectral characteristics, the accessibility of the methionine residues, the resistance of the protein to proteolysis by trypsin and the antigenic behaviour of RNAase-A as a result of the esterification of these two carboxy groups. Dimethyl RNAase-A exhibited only 65% of the specific activity of RNAase-A, but still had the same Km value for both RNA and 2′:3′-cyclic CMP. However, the Vmax. was decreased by about 35%. On careful hydrolysis of the methyl ester groups at pH9.5, dimethyl RNAase-A was converted back into RNAase-A. Limited proteolysis of dimethyl RNAase-A by subtilisin resulted in the formation of an active RNAase-S-type derivative, namely dimethyl RNAase-S, which was chromatographically distinct from dimethyl RNAase-A and had very nearly the same enzymic activity as dimethyl RNAase-A. Fractionation of dimethyl RNAase-S by trichloroacetic acid yielded dimethyl RNAase-S-protein and dimethyl RNAase-S-peptide, both of which were inactive by themselves but regenerated dimethyl RNAase-S when mixed together. Dimethyl RNAase-A-peptide was identical with RNAase-S-peptide. RNAase-S-protein could be generated from dimethyl RNAase-S-protein by careful hydrolysis of the methyl ester groups at pH9.5. The interaction of dimethyl RNAase-S-protein with RNAase-S-peptide appears to be about 4-fold weaker than that between the RNAase-S-protein and RNAase-S-peptide. Conceivably, the binding of the S-peptide ‘tail’ of dimethyl RNAase-A with the remainder of the molecule is similarly weaker than that in RNAase-A, and this brings about subtle changes in the geometrical orientation of the active-site amino acid residues of these modified methyl ester derivatives. It is suggested that these changes could be responsible for the generation of the catalytically less-efficient RNAase-A and RNAase-S molecules (dimethyl RNAase-A and dimethyl RNAase-S respectively).

Study on Detection Methods for Chlorine Precipitation during Biomass and Coal Co-Combustion

2012 ◽  
Vol 229-231 ◽  
pp. 1423-1426
Author(s):  
Yong Zheng Wang ◽  
Lei Jiang ◽  
Mao Zhen Yue ◽  
Su Fang Bian
Keyword(s):  
Silver Nitrate ◽  
Lower Limit ◽  
Spectrophotometric Method ◽  
Flue Gas ◽  
High Sensitivity ◽  
Volumetric Analysis ◽  
Sample Solution ◽  
Detection Methods ◽  
Multiple Measurements ◽  
Blend Fuel

In this paper, three detection methods were analyzed to determine the chlorine precipitation from the flue gas: Silver nitrate volumetric analysis (SNVA), Volhard method (VM) and Mercuric thiocyanate spectrophotometric method (MTSM). Results indicated that SNVA and VM were simple and convenient, but unsuitable for the detection of blend fuel due to the high lower limit. MTSM was suitable for biomass and coal co-combustion for its low lower limit and high sensitivity. In addition, MTSM needed less sample solution, which made it more suitable for multiple measurements to reduce errors, and the maximum proportional error was only 3.5%.

scholarly journals Spectrophotometric determination of atenolol via oxidation and bleaching color reaction for methyl red dye

2021 ◽  
Vol 2063 (1) ◽  
pp. 012008
Author(s):  
S A Zakaria ◽  
R A Zakaria ◽  
N S Othman
Keyword(s):  
Spectrophotometric Determination ◽  
Spectrophotometric Method ◽  
Molar Absorptivity ◽  
Sample Solution ◽  
Methyl Red ◽  
Suggested Procedure ◽  
Excess Quantity ◽  
Red Dye ◽  
Sensitive Spectrophotometric Method

Abstract A selective and sensitive spectrophotometric method has been suggested for the quantitative assay of atenolol (ATNL) as pure and in its manufactural formulation(Tablet). The suggested procedure included oxidation of ATNL with an excess quantity of the oxidant N-bromosuccinimide (NBS), and then the excess of NBS was occupied in bleaching the color of methyl red dye(MRD), then measuring the absorbance of remaining MRD at 518 nm. The absorbance of the unbleached color of MRD corresponds to the ATNL concentration in the sample solution. Beer’s law was followed in the range of 0.1-2.0 μg.ml−1with molar absorptivity value equal to 8.8864x104 l.mol−1. cm−1. The suggested method was applied to the assay of ATNL in commercial tablets, with satisfactory results.

Effects of bovine pancreatic ribonuclease A, S protein, and S peptide on activation of purified rat hepatic glucocorticoid-receptor complexes

Biochemistry ◽  
1986 ◽  
Vol 25 (20) ◽  
pp. 5955-5961 ◽  
Author(s):  
Thomas J. Schmidt ◽  
E. E. Diehl ◽  
C. J. Davidson ◽  
Michael J. Puk ◽  
M. L. Webb ◽  
...  
Keyword(s):  
Glucocorticoid Receptor ◽  
Ribonuclease A ◽  
S Protein ◽  
Pancreatic Ribonuclease ◽  
Receptor Complexes ◽  
Pancreatic Ribonuclease A

scholarly journals 15 N backbone dynamics of the S-peptide from ribonuclease A in its free and S-protein bound forms: Toward a site-specific analysis of entropy changes upon folding

1998 ◽  
Vol 7 (2) ◽  
pp. 389-402 ◽  
Author(s):  
Andrei T. Alexandrescu ◽  
Klara Rathgeb-Szabo ◽  
Wolfgang Jahnke ◽  
Therese Schulthess ◽  
Richard A. Kammerer ◽  
...  
Keyword(s):  
Ribonuclease A ◽  
Backbone Dynamics ◽  
Site Specific ◽  
S Protein ◽  
Entropy Changes ◽  
Specific Analysis ◽  
A Site

scholarly journals Subtilisin modification of monodeamidated ribonuclease-A

1977 ◽  
Vol 165 (2) ◽  
pp. 337-345 ◽  
Author(s):  
B. N. Manjula ◽  
A. Seetharama Acharya ◽  
Paul J. Vithayathil
Keyword(s):  
Acid Treatment ◽  
Structural Changes ◽  
Limited Proteolysis ◽  
Ribonuclease A ◽  
Enzymic Activity ◽  
Initial Reaction ◽  
S Protein ◽  
Acidic Solutions ◽  
Peptide Region ◽  
Protein Part

Limited proteolysis of RNAase-Aa1 (monodeamidated ribonuclease-A) by subtilisin results in the formation of an active RNAase-S type of derivative, namely RNAase-Aa1S. RNAase-Aa1S was chromatographically distinct from RNAase-S, but exhibited very nearly the same enzymic activity, antigenic conformation and susceptibility to trypsin as did RNAase-S. Fractionation of RNAase-Aa1S by trichloroacetic acid yielded RNAase-Aa1S-protein and RNAase-Aa1S-peptide, both of which are inactive by themselves, but regenerate active RNAase-Aa1S′ when mixed together. RNAase-Aa1S-peptide was identical with RNAase-S-peptide, whereas the protein part was distinct from that of RNAase-S-protein. Titration of RNAase-Aa1S-protein with S-peptide exhibited slight but noticeably weaker binding of the peptide to the deamidated S-protein as compared with that of native protein. Unlike the subtilisin digestion of RNAase-A, which gives nearly 100% conversion into RNAase-S, the digestion of RNAase-Aa1 gives only a 50% conversion. The resistance of RNAase-Aa1 to further subtilisin modification after 50% conversion is apparently due to the interaction of RNAase-Aa1 with its subtilisin-modified product. RNAase-S was also found to undergo activity and structural changes in acidic solutions, similar to those of RNAase-A. The initial reaction product (RNAase-Sa1) isolated by chromatography was not homogeneous. Unlike the acid treatment of RNAase-A, which affected only the S-protein part, the acid treatment of RNAase-S affected both the S-protein and the S-peptide region of the molecule.

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