19F nuclear magnetic resonance studies of the interaction of inhibitors with chymotrypsin. Derivatives of tryptophan and phenylalanine

1978 ◽  
Vol 31 (10) ◽  
pp. 2167 ◽  
Author(s):  
BC Nicholson ◽  
TM Spotswood
Keyword(s):  
Nuclear Magnetic Resonance ◽  
Magnetic Resonance ◽  
Least Squares Method ◽  
Competitive Inhibition ◽  
Binding Parameters ◽  
Linear Least Squares ◽  
Magnetic Resonance Studies ◽  
Ph Values ◽  
Derivatives Of ◽  
Tryptophan Derivatives

The binding of the inhibitors N-trifluoroacetyltryptophan, N- trifluoroacetylphenylalanine, N-acetyl-tryptophan and N- acetylphenylalanine to chymotrypsin has been studied by 19F N.M.R. spectroscopy at several pH values. Methods for determining the binding parameters, KI and ΔB, including a model for enzyme oligomerization and competitive inhibition from a second inhibitor, are discussed and a general non-linear least-squares method is presented. Values of KI and ΔB are recorded for D and L enantiomers of tryptophan derivatives and for D-phenylalanine derivatives. The results are discussed in terms of a model for the aromatic binding site of chymotrypsin.

19F nuclear magnetic resonance studies of the interaction of inhibitors with chymotrypsin. Ring-fluorinated derivatives of N-trifluoroacetylphenylalanine

1978 ◽  
Vol 31 (10) ◽  
pp. 2179 ◽  
Author(s):  
M Tsavalos ◽  
BC Nicholson ◽  
TM Spotswood
Keyword(s):  
Amino Acids ◽  
Nuclear Magnetic Resonance ◽  
Magnetic Resonance ◽  
Chemical Shift ◽  
Active Site ◽  
Enzyme Inhibitor ◽  
Aromatic Amino Acids ◽  
Binding Parameters ◽  
Magnetic Resonance Studies ◽  
Derivatives Of

The complexes formed between chymotrypsin and the doubly fluorine- labelled inhibitors, o-, m- and p-fluoro-N-trifluoroacetyl-D- phenylalanine and 2,4-difluoro-N-trifluoroacetyl-D-phenylalanine, have been characterized by 19F N.M.R. spectroscopy and binding parameters, ΔB and KI, have been derived. The results confirm the importance of the amido binding site in orienting aromatic amino acids at the active site of chymotrypsin. Changes in ΔB, the change in chemical shift of the enzyme-bound inhibitor, are shown to be a very sensitive probe of enzyme-inhibitor interactions.

Etude conformationnelle par résonance magnétique nucléaire du carbone 13 de peptides à activité antalgique

1980 ◽  
Vol 58 (11) ◽  
pp. 1241-1246 ◽  
Author(s):  
Robert René Smolders ◽  
Roland Coomans ◽  
Françoise Jacquemotte ◽  
Yves Van Haverbeke ◽  
André Maquestiau ◽  
...  
Keyword(s):  
Nuclear Magnetic Resonance ◽  
Magnetic Resonance ◽  
Trans Conformation ◽  
Magnetic Resonance Studies ◽  
Ph Values ◽  
Résonance Magnétique ◽  
Nuclear Magnetic

13C Nuclear magnetic resonance studies of proline peptides with central antalgic activity (Pro-Arg, Arg-Pro, Pro-Arg-Pro, Pro-Lys-Pro) indicate a predominance of trans conformation at all pH values; but their physiological activities appear to be related to the ability of the C-terminal proline peptides to assume the cis conformation.

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