Warning: Undefined variable $zfal in C:\Inetpub\vhosts\kidney.de\httpdocs\mlpefetch.php on line 525
Deprecated: str_replace(): Passing null to parameter #3 ($subject) of type array|string is deprecated in C:\Inetpub\vhosts\kidney.de\httpdocs\mlpefetch.php on line 525
Warning: Undefined variable $sterm in C:\Inetpub\vhosts\kidney.de\httpdocs\mlpefetch.php on line 530
 free
Warning: Undefined variable $sterm in C:\Inetpub\vhosts\kidney.de\httpdocs\mlpefetch.php on line 531
 free
 free
Warning: file_get_contents(http://eutils.ncbi.nlm.nih.gov/entrez/eutils/elink.fcgi?dbfrom=pubmed&id=21182991&cmd=llinks): Failed to open stream: HTTP request failed! HTTP/1.1 429 Too Many Requests
in C:\Inetpub\vhosts\kidney.de\httpdocs\mlpefetch.php on line 445
 
English Wikipedia
Nephropedia Template TP (
Twit Text
DeepDyve
Pubget Overpricing |  
lüll
The PLP cofactor: lessons from studies on model reactions Richard JP; Amyes TL; Crugeiras J; Rios ABiochim Biophys Acta 2011[Nov]; 1814 (11): 1419-25Experimental probes of the acidity of weak carbon acids have been developed and used to determine the carbon acid pK(a)s of glycine, glycine derivatives and iminium ion adducts of glycine to the carbonyl group, including 5'-deoxypyridoxal (DPL). The high reactivity of the DPL-stabilized glycyl carbanion towards nucleophilic addition to both DPL and the glycine-DPL iminium ion favors the formation of Claisen condensation products at enzyme active sites. The formation of the iminium ion between glycine and DPL is accompanied by a 12-unit decrease in the pK(a) of 29 for glycine. The complicated effects of formation of glycine iminium ions to DPL and other aromatic and aliphatic aldehydes and ketones on carbon acid pK(a) are discussed. These data provide insight into the contribution of the individual pyridine ring substituents to the catalytic efficiency of DPL. It is suggested that the 5'-phosphodianion group of PLP may play an important role in enzymatic catalysis of carbon deprotonation by providing up to 12 kcal/mol of binding energy that is utilized to stabilize the transition state for the enzymatic reaction. This article is part of a Special Issue entitled: Pyridoxal Phospate Enzymology.|*Models, Chemical[MESH]|Catalysis[MESH]|Glycine/chemistry[MESH]|Pyridoxal Phosphate/*chemistry[MESH] |
