Formation of substituted 1-Benzazepine-2,5-diones from derivatives of kynurenine

1978 ◽  
Vol 31 (2) ◽  
pp. 439 ◽  
Author(s):  
DE Rivett ◽  
FHC Stewart

Several N-protected DL-kynurenine derivatives have been converted into 3-substituted 3,4-dihydro-1H-1-benzazepine-2,5-diones by thermal cyclization. This reaction was found to proceed less readily than the analogous formation of 1,4-benzodiazepine-2,5-diones from o- aminobenzoylamino acids. The incidence of specific peptide bond cleavage involving these cyclizations was investigated with model compounds.

1992 ◽  
Vol 11 (1) ◽  
pp. 45-50 ◽  
Author(s):  
Chi-Yue Wu ◽  
Shui-Tein Chen ◽  
Shyh-Horng Chiou ◽  
Kung-Tsung Wang

1972 ◽  
Vol 112 (2) ◽  
pp. 940-949 ◽  
Author(s):  
Marilyn Wingard ◽  
Gary Matsueda ◽  
R. S. Wolfe

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Riley B. Peacock ◽  
Taylor McGrann ◽  
Marco Tonelli ◽  
Elizabeth A. Komives

AbstractSerine proteases catalyze a multi-step covalent catalytic mechanism of peptide bond cleavage. It has long been assumed that serine proteases including thrombin carry-out catalysis without significant conformational rearrangement of their stable two-β-barrel structure. We present nuclear magnetic resonance (NMR) and hydrogen deuterium exchange mass spectrometry (HDX-MS) experiments on the thrombin-thrombomodulin (TM) complex. Thrombin promotes procoagulative fibrinogen cleavage when fibrinogen engages both the anion binding exosite 1 (ABE1) and the active site. It is thought that TM promotes cleavage of protein C by engaging ABE1 in a similar manner as fibrinogen. Thus, the thrombin-TM complex may represent the catalytically active, ABE1-engaged thrombin. Compared to apo- and active site inhibited-thrombin, we show that thrombin-TM has reduced μs-ms dynamics in the substrate binding (S1) pocket consistent with its known acceleration of protein C binding. Thrombin-TM has increased μs-ms dynamics in a β-strand connecting the TM binding site to the catalytic aspartate. Finally, thrombin-TM had doublet peaks indicative of dynamics that are slow on the NMR timescale in residues along the interface between the two β-barrels. Such dynamics may be responsible for facilitating the N-terminal product release and water molecule entry that are required for hydrolysis of the acyl-enzyme intermediate.


1979 ◽  
Author(s):  
M.J. Lindhout ◽  
C. M. Jackson

In order to understand the function of activated factor V in the prothrombinase complex, we isolated the activation products obtained by action of thrombin and RVV-V on factor V and studied their functional properties. Factor V isolated from plasma by means of ion-exchange chromatography, a Ca-oxalate adsorption step and gelfiltration was homogenous in SDS-gelelectrophoresis (apparent MW 360,000, with and without reduction). Increase in factor V activity upon action by RVV-V is correlated with a single peptide bond cleavage, resulting in a 270,000 dalton and a 80,000 dalton component. Additional proteolysis of factor Va(RVV/V)’ by thrombin results in a further cleavage of the high MW component into peptides with MW's of 72,000, 94,000 and about 150,000 without a furth~r increase in factor V activity. Whereas none of the isolated peptides reveal factor Va activity, activity would be generated by a recombination in the presence of Ca2+ of the 94,000 MW or 270,000 MW component with the 80,000 component. Action of thrombin alone on factor V results in peptides of MW 72,000, 80,000, 94,000 and a peptide very rich in carbohydrate with an apparent MW of 150,000.


1982 ◽  
Vol 37 (3) ◽  
pp. 380-385 ◽  
Author(s):  
G. N. Schrauzer ◽  
Laura A. Hughes ◽  
Norman Strampach

Abstract Colorless alkylmolybdates(VI) of composition R-MoO3-are generated in aqueous solutions by the alkaline hydrolysis of complexes R-Mo(Bpy)(0)2Br(Bpy = 2,2′-bipyridyl, R = CH3 and higher alkyl). At room temperature in alkaline aqueous solution, the new organometallic derivatives of oxomolybdate(VI) are remarkably resistant against Mo-C bond hydrolysis. Decomposition occurs more rapidly on heating, affording unrearranged alkanes according to the eq.: R-MoO3- + OH-→RH + Mo04=. In acidic solutions, the methylmolybdate(VI) species decomposes with the formation of a mixture of methane and ethane while higher alkylmolybdates carrying hydrogen in the β-position relative to molybdenum undergo Mo-C bond heterolysis by way of β-elimina-tion: R-CH2CH2-MoO3 → Mo+4 (aq) + H+ + R-CH = CH2. The Mo-C bond of alkylmolybdates is resistant to oxidants but is very sensitive to cleavage under reducing conditions. Reductive Mo-C bond cleavage occurs particularly rapidly in the presence of thiols and reduced ferredoxin model compounds. The latter reactions simulate the terminal steps of hydrocarbon producing reactions of nitrogenase with alternate substrates such as CN-, R-CN or R-NC, confirming previous mechanistic conclusions concerning the mechanism of nitrogenase action.


2016 ◽  
Vol 133 ◽  
pp. S426-S431 ◽  
Author(s):  
Mikhail M. Vorob’ev ◽  
Claire I. Butré ◽  
Stefano Sforza ◽  
Peter A. Wierenga ◽  
Harry Gruppen

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