Berggren K

References (3)

Title : Discovery of a Novel Microsomal Epoxide Hydrolase-Catalyzed Hydration of a Spiro Oxetane - Li_2016_Drug.Metab.Dispos_44_1341
Author(s) : Li XQ , Hayes MA , Gronberg G , Berggren K , Castagnoli N, Jr. , Weidolf L
Ref : Drug Metabolism & Disposition: The Biological Fate of Chemicals , 44 :1341 , 2016
Abstract : Oxetane moieties are increasingly being used by the pharmaceutical industry as building blocks in drug candidates because of their pronounced ability to improve physicochemical parameters and metabolic stability of drug candidates. The enzymes that catalyze the biotransformation of the oxetane moiety are, however, not well studied. The in vitro metabolism of a spiro oxetane-containing compound AZD1979 [(3-(4-(2-oxa-6-azaspiro[3.3]heptan-6-ylmethyl)phenoxy)azetidin-1-yl)(5-(4-ethoxy phenyl)-1,3,4-oxadiazol-2-yl)methanone] was studied and one of its metabolites, M1, attracted our interest because its formation was NAD(P)H independent. The focus of this work was to elucidate the structure of M1 and to understand the mechanism(s) of its formation. We established that M1 was formed via hydration and ring opening of the oxetanyl moiety of AZD1979. Incubations of AZD1979 using various human liver subcellular fractions revealed that the hydration reaction leading to M1 occurred mainly in the microsomal fraction. The underlying mechanism as a hydration, rather than an oxidation reaction, was supported by the incorporation of (18)O from H2 (18)O into M1. Enzyme kinetics were performed probing the formation of M1 in human liver microsomes. The formation of M1 was substantially inhibited by progabide, a microsomal epoxide hydrolase inhibitor, but not by trans-4-[4-(1-adamantylcarbamoylamino)cyclohexyloxy]benzoic acid, a soluble epoxide hydrolase inhibitor. On the basis of these results, we propose that microsomal epoxide hydrolase catalyzes the formation of M1. The substrate specificity of microsomal epoxide hydrolase should therefore be expanded to include not only epoxides but also the oxetanyl ring system present in AZD1979.
ESTHER : Li_2016_Drug.Metab.Dispos_44_1341
PubMedSearch : Li_2016_Drug.Metab.Dispos_44_1341
PubMedID: 27256986
Gene_locus related to this paper: human-EPHX1

Title : Substitutions of surface amino acid residues of cutinase probed by aqueous two-phase partitioning - Berggren_2000_Biochim.Biophys.Acta_1481_317
Author(s) : Berggren K , Egmond MR , Tjerneld F
Ref : Biochimica & Biophysica Acta , 1481 :317 , 2000
Abstract : The surface properties of a protein are often crucial for recognition and interaction with other molecules. Important functional residues can be identified by mutational analysis. There is a need for rapid methods to study protein surfaces and surface changes due to mutations. Partitioning in aqueous two-phase systems has the potential to be used in this respect since protein partitioning depends on the surface properties of the protein. The influence of surface-exposed amino acid residues in protein partitioning has been studied with cutinase variants, which differed in one or several amino acid residues as a result of site-directed mutagenesis. The solvent accessibility of the mutated residues was determined with a computer program, Graphical Representation and Analysis of Surface Properties. The aqueous two-phase system was composed of dextran and a random copolymer of ethylene oxide and propylene oxide. It was shown, for the first time, to what extent surface-exposed amino acid residues influence the partition coefficient in an aqueous two-phase system. The effect on partitioning could be described only taking into account solvent accessibility and type of residue substitution. The results demonstrate that the system can be used to detect conformational changes in mutant proteins since the expected effect on partitioning due to a mutation can be calculated. The aqueous two-phase system used here does indeed provide a rapid and convenient method to study protein surfaces and slight surface changes due to mutations.
ESTHER : Berggren_2000_Biochim.Biophys.Acta_1481_317
PubMedSearch : Berggren_2000_Biochim.Biophys.Acta_1481_317
PubMedID: 11018723

Title : Partitioning of peptides and recombinant protein-peptide fusions in thermoseparating aqueous two-phase systems: effect of peptide primary structure - Berggren_2000_J.Chromatogr.B.Biomed.Sci.Appl_743_295
Author(s) : Berggren K , Nilsson A , Johansson G , Bandmann N , Nygren PA , Tjerneld F
Ref : Journal of Chromatography B Biomed Sci Appl , 743 :295 , 2000
Abstract : Genetic engineering has been used for fusion of peptides, with different length and composition, on a protein to study the effect on partitioning in an aqueous two-phase system. The system was composed of dextran and the thermoseparating ethylene oxide-propylene oxide random copolymer, EO30P070. Peptides containing tryptophan, proline, arginine or aspartate residues were fused at the C-terminus of the recombinant protein ZZ-cutinase. The aim was to find effective tags for the lipolytic enzyme cutinase for large-scale extraction. The target protein and peptide tags were partitioned separately and then together in the fusion proteins in order to gain increased understanding of the influence of certain amino acid residues on the partitioning. The salt K2SO4 was used to reduce the charge dependent salt effects on partitioning and to evaluate the contribution to the partition coefficient from the hydrophobic-hydrophilic properties of the amino acid residues. The effect of Trp on peptide partitioning was independent of the difference in primary structure for (Trp)n, (Trp-Pro)n, (Ala-Trp-Trp-Pro)n and was only determined by the number of Trp. The effect of the charged residues, Arg and Asp, was dependent on the surrounding residues, i.e. if they were situated next to Trp or not. The partitioning behaviour observed for the peptides was qualitatively and in some cases also quantitatively the same as for the fusion proteins. The effect of the salts sodium perchlorate and triethylammonium phosphate on the partitioning was also studied. The salt effects observed for the peptides were qualitatively similar to the effects observed for the fusion proteins.
ESTHER : Berggren_2000_J.Chromatogr.B.Biomed.Sci.Appl_743_295
PubMedSearch : Berggren_2000_J.Chromatogr.B.Biomed.Sci.Appl_743_295
PubMedID: 10942300