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At least 163 records · Page 9Linked to original sources
PubMed1993

A left-handed crossover involved in amidohydrolase catalysis. Crystal structure of Erwinia chrysanthemi L-asparaginase with bound L-aspartate.

The crystal structure of L-asparaginase from Erwinia chrysanthemi in the presence and absence of L-aspartate was determined at 1.8 A resolution. Conserved residues in a left-handed crossover (a rare occurrence in protein structures) link pairs of dimers into the catalytically active tetrameric form of the enzyme. The structure of ErA containing bound aspartic acid shows that this unusual strand connectivity is an essential part of the active site architecture, responsible for releasing the product of the enzymatic hydrolysis. The orientation of the bound aspartate indicates for the first time a threonine residue as a catalytic nucleophile.

Amidohydrolases↗
PubMed2000

Pharmacological properties of rat brain fatty acid amidohydrolase in different subcellular fractions using palmitoylethanolamide as substrate.

In the present study, the pharmacological properties of fatty acid amide hydrolase (FAAH) in subcellular fractions of rat brain were investigated using palmitoylethanolamide (PEA) and arachidonyl ethanolamide (anandamide, AEA) as substrates. FAAH hydrolysed [(3)H]PEA in crude homogenates with median K(m) and V(max) values of 2.9 microM and 2.14 nmol.(mg protein)(-1).min(-1), respectively. [(3)H]PEA hydrolysis was inhibited both by non-radioactive AEA (with a K(i) value very similar to the K(m) value for [(3)H]AEA as substrate using the same assay) and by R(-)ibuprofen (mixed-type inhibition K(i) and K'(i) values 88 and 720 microM, respectively). FAAH activity towards both [(3)H]PEA and [(3) myelin = cytosol, but there were no differences between the relative activities towards the two substrates in any of the fractions. [(3)H]PEA hydrolysis in mitochondrial, myelin, microsomal, and synaptosomal fractions was inhibited by oleyl trifluoromethylketone, phenylmethylsulphonyl fluoride, and the R(-)- and S(+)-enantiomers of the nonsteroidal anti-inflammatory drug ibuprofen, with mean IC(50) values in the ranges 0.028-0.041, 0.37-0.52, 67-110, and 130-260 microM, respectively. It is concluded that the pharmacological properties of FAAH in the different subcellular fractions are very similar.

Amides↗
PubMed1998

Anandamide amidohydrolase reacting with 2-arachidonoylglycerol, another cannabinoid receptor ligand.

Two endogenous ligands for cannabinoid receptors, anandamide (arachidonylethanolamide) and 2-arachidonoylglycerol, lose their biological activities by enzymatic hydrolysis. A cDNA for a rat liver enzyme hydrolyzing anandamide as well as oleamide was overexpressed in COS-7 cells. When the particulate fraction was allowed to react with 2-arachidonoylglycerol, arachidonic acid was produced. In contrast, this hydrolytic reaction did not occur with the control cells. The hydrolysis of 2-arachidonoylglycerol proceeded about 4-fold faster than the anandamide hydrolysis with a Km value as low as 6 microM and an optimal pH of 10. Phenylmethylsulfonyl fluoride and methyl arachidonyl fluorophosphonate inhibited the hydrolysis of both anandamide and 2-arachidonoylglycerol in parallel. Furthermore, the hydrolysis of [14C]2-arachidonoylglycerol was inhibited by anandamide dose-dependently. These results suggest that anandamide and 2-arachidonoylglycerol can be inactivated by the same enzyme.

Amidohydrolases↗
PubMed2003

Amidase domains from bacterial and phage autolysins define a family of gamma-D,L-glutamate-specific amidohydrolases.

Several phage-encoded peptidoglycan hydrolases have been found to share a conserved amidase domain with a variety of bacterial autolysins (N-acetylmuramoyl-L-alanine amidases), bacterial and eukaryotic glutathionylspermidine amidases, gamma-D-glutamyl-L-diamino acid endopeptidase and NLP/P60 family proteins. All these proteins contain conserved cysteine and histidine residues and hydrolyze gamma-glutamyl-containing substrates. These cysteine residues have been shown to be essential for activity of several of these amidases and their thiol groups apparently function as the nucleophiles in the catalytic mechanisms of all enzymes containing this domain. The CHAP (cysteine, histidine-dependent amidohydrolases/peptidases) superfamily includes a variety of previously uncharacterized proteins, including the tail assembly protein K of phage lambda. Some members of this superfamily are important surface antigens in pathogenic bacteria and might represent drug and/or vaccine targets.

Amidohydrolases↗
PubMed1969

Distribution, purification and properties of 1-aspartamido-beta-N-acetylglucosamine amidohydrolase.

1. The activity of the enzyme that splits 2-acetamido-1-l-beta-aspartamido-1,2-dideoxy-beta-d- glucose (1-aspartamido-beta-N-acetylglucosamine) was measured in tissues from different mammalian species. 2. The enzyme from an aqueous extract of rat liver was purified 150-fold in 56% yield. 3. Optimum activity for the hydrolysis of 1-aspartamido-beta-N-acetylglucosamine was at pH7, and ammonia and N-acetylglucosamine were liberated in equimolar amounts. At pH8.5, 1-amino-N-acetylglucosamine was the only sugar produced after short periods of incubation. On prolonged incubation there was spontaneous liberation of ammonia from this compound. 4. It is concluded that the enzyme is an amidase.

Amidohydrolases↗
PubMed1999

The use of hipO, encoding benzoylglycine amidohydrolase (hippuricase), as a reporter of gene expression in Campylobacter coli.

A novel integrative promoter probe vector which utilizes the Campylobacter jejuni hipO gene as a reporter of gene expression was developed as a genetic tool in Campylobacter coli. The utility of the system was demonstrated by coupling expression of the hipO reporter to the promoters of flaA, flaB and katA. Subsequently, expression of these genes could be monitored accurately from chromosomally-borne transcriptional fusions using a simple non-destructive colorimetric assay. The system should serve as a useful tool for studying the response of Camp. coli to environmental stresses.

Amidohydrolases↗