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Title: C-8 Modifications of 3-alkyl-1,8-dibenzylxanthines as Inhibitors of Human Cytosolic Phosphoenolpyruvate Carboxykinase

Abstract

New modifications on the C-8 4-aminobenzyl unit of the previously reported 3-alkyl-1,8-dibenzylxanthine inhibitors of cPEPCK are presented. The most active compound reported here is the 5-chloro-1,3-dimethyl-1H-pyrazole-4-sulfonic acid amide derivative 2 with an IC{sub 50} of 0.29 {+-} 0.08 {mu}M. An X-ray analysis of a heteroaromatic sulfonamide is presented showing a new {pi}-{pi} interaction.

Authors:
; ; ; ; ; ; ; ; ;
Publication Date:
Research Org.:
Brookhaven National Laboratory (BNL) National Synchrotron Light Source
Sponsoring Org.:
Doe - Office Of Science
OSTI Identifier:
930435
Report Number(s):
BNL-81179-2008-JA
Journal ID: ISSN 0960-894X; TRN: US200904%%541
DOE Contract Number:
DE-AC02-98CH10886
Resource Type:
Journal Article
Resource Relation:
Journal Name: BioOrganic and Medicinal Chemistry Letters; Journal Volume: 17; Journal Issue: 14
Country of Publication:
United States
Language:
English
Subject:
59 BASIC BIOLOGICAL SCIENCES; AMIDES; ENZYMES; ENZYME INHIBITORS; MODIFICATIONS; PHOSPHOENOLPYRUVATE; SULFONAMIDES; national synchrotron light source

Citation Formats

Pietranico,S., Foley, L., Huby, N., Yun, W., Dunten, P., Vermeulen, J., Wang, P., Toth, K., Ramsey, G., and et al.. C-8 Modifications of 3-alkyl-1,8-dibenzylxanthines as Inhibitors of Human Cytosolic Phosphoenolpyruvate Carboxykinase. United States: N. p., 2007. Web. doi:10.1016/j.bmcl.2007.05.013.
Pietranico,S., Foley, L., Huby, N., Yun, W., Dunten, P., Vermeulen, J., Wang, P., Toth, K., Ramsey, G., & et al.. C-8 Modifications of 3-alkyl-1,8-dibenzylxanthines as Inhibitors of Human Cytosolic Phosphoenolpyruvate Carboxykinase. United States. doi:10.1016/j.bmcl.2007.05.013.
Pietranico,S., Foley, L., Huby, N., Yun, W., Dunten, P., Vermeulen, J., Wang, P., Toth, K., Ramsey, G., and et al.. Mon . "C-8 Modifications of 3-alkyl-1,8-dibenzylxanthines as Inhibitors of Human Cytosolic Phosphoenolpyruvate Carboxykinase". United States. doi:10.1016/j.bmcl.2007.05.013.
@article{osti_930435,
title = {C-8 Modifications of 3-alkyl-1,8-dibenzylxanthines as Inhibitors of Human Cytosolic Phosphoenolpyruvate Carboxykinase},
author = {Pietranico,S. and Foley, L. and Huby, N. and Yun, W. and Dunten, P. and Vermeulen, J. and Wang, P. and Toth, K. and Ramsey, G. and et al.},
abstractNote = {New modifications on the C-8 4-aminobenzyl unit of the previously reported 3-alkyl-1,8-dibenzylxanthine inhibitors of cPEPCK are presented. The most active compound reported here is the 5-chloro-1,3-dimethyl-1H-pyrazole-4-sulfonic acid amide derivative 2 with an IC{sub 50} of 0.29 {+-} 0.08 {mu}M. An X-ray analysis of a heteroaromatic sulfonamide is presented showing a new {pi}-{pi} interaction.},
doi = {10.1016/j.bmcl.2007.05.013},
journal = {BioOrganic and Medicinal Chemistry Letters},
number = 14,
volume = 17,
place = {United States},
year = {Mon Jan 01 00:00:00 EST 2007},
month = {Mon Jan 01 00:00:00 EST 2007}
}
  • Phosphoenolpyruvate carboxykinase (GTP) (PEPCK) specifically utilizes a guanosine or inosine nucleotide as a substrate, yet it does not share extended sequence homology with other GTP-binding proteins, and the molecular basis for its nucleotide specificity is not understood. In an effort to locate the enzyme's nucleotide-binding site, the authors have studied the interaction of cytosolic PEPCK from rat liver with the photoprobe 8-azidoGTP, which fulfills the criteria of a specific photoaffinity label for PEPCK. The photoprobe binds reversibly to the enzyme prior to modification and at low concentrations causes greater than 60% inactivation-GTP provides nearly complete protection against inactivation by 8-azidoGTP,more » whereas phosphoenolpyruvate and metal ions provide partial protection. In addition, the photoprobe is a substrate for the enzyme and has a K{sub m} similar to that for GTP. However, the extent of covalent modification by ({sup 32}P)8-azido-GTP as measured by three independent techniques is significantly lower than the extent of enzyme inactivation. Further investigation of this anomaly has revealed that the loss in enzymatic activity is caused by modification of a critical cysteine residue in a reaction that does not terminate with covalent attachment of the photolabel. Quantitation of the total free thiols of modified PEPCK shows that 2 mol of cysteine is lost per mole of inactivated enzyme. These results indicate that the photoinactivation of PEPCK by 8-azidoGTP is caused by the formation of an intramolecular cystine disulfide bridge, thus providing evidence for the existence of a pair of proximal cysteine residues within the GTP-binding site. The interaction of cysteine residues with the reactive photogenerated derivatives of 8-azidopurines is discussed.« less
  • No abstract prepared.
  • Cytoplasmic liver phosphoenolpyruvate carboxykinase (GTP) (PEPCK) catalyzes a rate-limiting step in gluconeogenesis. Primers derived from the rat liver PEPCK sequence were used to amplify a portion of the human liver cDNA and to screen a YAC library of human genomic DNA. The sequences of human and rat PEPCK CDNA differed at 16% of the nucleotides compared (45/291). Analysis of a human/rodent hybrid mapping panel demonstrated concordant segregation of PCK1 with chromosome 20. Fluorescence in situ hybridization with YAC DNA further localized PCK1 to subband 20q13.2. 4refs., 1 fig. 1 tab.
  • The human PCK 1 gene encoding phosphoenolpyruvate carboxykinase (GTP) (PEPCK) was isolated and sequenced. There is 91% amino acid sequence identity (567/622 residues) between the human and the rat proteins, with conservation of intron/exon borders. A polymorphic dinucleotide microsatellite with the structure (CA)[sub 16](TA)[sub 5](CA) was identified in the 3[prime] untranslated region of the cloned human PCK1 gene. This highly informative genetic marker has an estimated PIC value of 0.79 and heterozygosity of 0.81. Analysis of the RW pedigree demonstrated recombination between PCK1 and the MODY gene on chromosome 20. Multipoint linkage analysis of the reference pedigrees of the Centremore » d'Etude du Polymorphisme Humain localized PCK1 on the genetic map of chromosome 20 at a position distal to markers that are closely linked to MODY. PCK1 is part of a conserved linkage group on mouse Chromosome 2 with identical gene order but expanded length in the human genome. 34ref., 7 figs., 1 tab.« less