A5080654908- Enzyme Catalysis and Immobilization
- X-ray Diffraction in Crystallography
- Crystallization and Solubility Studies
- Infective Endocarditis Diagnosis and Management
- Enzyme Structure and Function
- Bacterial Identification and Susceptibility Testing
- Neonatal Health and Biochemistry
- Drug Transport and Resistance Mechanisms
- Adenosine and Purinergic Signaling
- Streptococcal Infections and Treatments
- Enzyme Production and Characterization
- Pharmacogenetics and Drug Metabolism
- Monoclonal and Polyclonal Antibodies Research
- Synthesis of β-Lactam Compounds
- Genomics and Phylogenetic Studies
- Biochemical and Molecular Research
- Analytical Methods in Pharmaceuticals
- Ocular Infections and Treatments
- Immune Response and Inflammation
- Carbohydrate Chemistry and Synthesis
- Antibiotics Pharmacokinetics and Efficacy
- Inflammatory mediators and NSAID effects
- Ion Transport and Channel Regulation
- Chemical Synthesis and Analysis
University Medical Center Groningen
2002-2016
University of Groningen
2002-2016
Biotechnology Institute
2009
Erasmus University Rotterdam
2002
Penicillin acylase of Escherichia coli catalyses the hydrolysis and synthesis β‐lactam antibiotics. To study role hydrophobic residues in these reactions, we have mutated three active‐site phenylalanines. Mutation αF146, βF24 βF57 to Tyr, Trp, Ala or Leu yielded mutants that were still capable hydrolysing chromogenic substrate 2‐nitro‐5‐[(phenylacetyl)amino]‐benzoic acid. Mutations on positions αF146 influenced both hydrolytic acyl transfer activity. This caused changes transferase/hydrolase...
In hepatocytes, cAMP/PKA activity stimulates the exocytic insertion of apical proteins and lipids biogenesis bile canalicular plasma membranes. Here, we show that displacement PKA-RIIalpha from Golgi apparatus severely delays trafficking protein MDR1 (P-glycoprotein), but not MRP2 (cMOAT), DPP IV 5'NT, to newly formed surfaces. addition, direct de novo synthesized glycosphingolipid analogues surface is inhibited. Instead, glucosylceramide are rerouted basolateral via a vesicular pathway,...
Penicillin acylase catalyses the hydrolysis and synthesis of semisynthetic beta-lactam antibiotics via formation a covalent acyl-enzyme intermediate. The kinetic mechanistic aspects these reactions were studied. Stopped-flow experiments with penicillin ampicillin analogues 2-nitro-5-phenylacetoxy-benzoic acid (NIPAOB) d-2-nitro-5-[(phenylglycyl)amino]-benzoic (NIPGB) showed that rate-limiting step in conversion G is acyl-enzyme. phenylacetyl- phenylglycyl-enzymes are hydrolysed rate...
The active site of penicillin acylase Escherichia coli contains two conserved arginine residues. function these arginines, alphaArg145 and betaArg263, was studied by site-directed mutagenesis kinetic analysis the mutant enzymes. mutants alphaArg145-->Leu (alphaArg145Leu), alphaArg145Cys alphaArg145Lys were normally processed exported to periplasm, whereas expression betaArg263Leu, betaArg263Asn betaArg263Lys yielded large amounts precursor protein in indicating that betaArg263 is crucial for...
α-Amino-acid ester hydrolases are multimeric enzymes of potential use in antibiotic production. Knowledge their structure could help to engineer these into economically viable biocatalysts. The α-amino-acid from Xanthomonas citri and Acetobacter turbidans have been crystallized. X. enzyme crystallizes a primitive monoclinic space group (unit-cell parameters = 90.1, b 125.8, c 132.1 Å, β 90.9°). A. both orthorhombic (a 99.1, 104.9, 284.9 Å) body-centred cubic with 342.2 Å. From enzymes,...
Residue phenylalanine 71 of the β-chain penicillin acylase from E. coli is involved in substrate binding and chiral discrimination its enantiomers. Different amino acid residues have been introduced at position βF71, mutants were studied with respect to their enantioselectivity specificity. Some demonstrated remarkably improved catalytic activity. Moreover, mutation βF71 residue allowed enhance enantioselectivity. The activity specific substrates was up 36 times, most notably for K, R, L...