Nuclear magnetic resonance of phosphorus compounds. VII. Evidence for steric effects on the phosphorus-31-selenium-77 coupling and phosphorus-31 chemical shifts

1973 ◽  
Vol 95 (3) ◽  
pp. 977-978 ◽  
Author(s):  
Robert P. Pinnell ◽  
Clifford A. Megerle ◽  
Stanley L. Manatt ◽  
Paulus A. Kroon
Keyword(s):  
Nuclear Magnetic Resonance ◽  
Magnetic Resonance ◽  
Chemical Shifts ◽  
Phosphorus Compounds ◽  
Steric Effects ◽  
Nuclear Magnetic

Phosphorus-31 nuclear magnetic resonance pH titration studies of the phosphoproteins tropomyosin and glycogen phosphorylase a

1983 ◽  
Vol 61 (6) ◽  
pp. 363-369 ◽  
Author(s):  
Hans. J. Vogel ◽  
William A. Bridger
Keyword(s):  
Nuclear Magnetic Resonance ◽  
Magnetic Resonance ◽  
Glycogen Phosphorylase ◽  
Chemical Shifts ◽  
Phosphorus Compounds ◽  
Hill Coefficient ◽  
Ph Titration ◽  
The Hill ◽  
Regulatory Sites ◽  
Nuclear Magnetic

31P nuclear magnetic resonance (NMR), pH titration studies of the phosphoproteins tropomyosin and glycogen phosphorylase a (in the presence of the inhibitor glucose) show that the resonances for the phosphoserine regulatory sites shift with pH. Analysis of line widths indicates that both residues have considerable mobility. These results are in agreement with studies on similar phosphorylated sites on other proteins, leading us to propose that mobility is a general feature of such regulatory sites. pH titration studies on a series of model compounds have indicated that an empirical correlation exists between the Hill coefficient n (a measure of the cooperativity of the titration curve) and the presence of charged groups in the vicinity of the phosphoryl moiety. Moreover, these studies showed that within one class of similarly substituted phosphorus compounds the chemical shifts, the titration behaviour, and the [Formula: see text] were comparable and allow for easy identification of these compounds. The [Formula: see text] values for phosphoserine residues of proteins are in general slightly higher than those of phosphomonoester-containing small compounds. The titration data prompt our estimation that the maximal amount of energy associated with a salt linkage between a phosphoseryl side chain and a positively charged group is about 5 kcal (1 cal = 4.1868 J).

Carbon-13 nuclear magnetic resonance examination of naphthalene derivatives. Assignments and analysis of substituent chemical shifts

1977 ◽  
Vol 42 (14) ◽  
pp. 2411-2418 ◽  
Author(s):  
William Kitching ◽  
Maxwell Bullpitt ◽  
David Gartshore ◽  
William Adcock ◽  
T. C. Khor ◽  
...  
Keyword(s):  
Nuclear Magnetic Resonance ◽  
Magnetic Resonance ◽  
Chemical Shifts ◽  
Magnetic Resonance Examination ◽  
Naphthalene Derivatives ◽  
Nuclear Magnetic

Nuclear Magnetic Resonance Chemical Shifts of some Monosubstituted Isothiazoles

1975 ◽  
Vol 53 (4) ◽  
pp. 596-603 ◽  
Author(s):  
Roderick E. Wasylishen ◽  
Thomas R. Clem ◽  
Edwin D. Becker
Keyword(s):  
Nuclear Magnetic Resonance ◽  
Magnetic Resonance ◽  
Chemical Shifts ◽  
Substituent Effects ◽  
Charge Densities ◽  
Monosubstituted Benzenes ◽  
Proton Chemical Shifts ◽  
Nuclear Magnetic

Carbon-13 and proton chemical shifts have been measured for several monosubstituted isothiazoles. Substituent effects upon these chemical shifts are compared with those observed for monosubstituted benzenes, pyridines, and thiophenes. In general the observed substituent effects in the isothiazoles and thiophenes closely parallel one another. Correlations between the observed carbon-13 Chemical shifts and CNDO/2 calculated charge densities are examined.

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