Tjaard Pijning

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The human cartilage glycoprotein-39 (HCgp-39 or YKL40) is expressed by synovial cells and macrophages during inflammation. Its precise physiological role is unknown. However, it has been proposed that HCgp-39 acts as an autoantigen in rheumatoid arthritis, and high expression levels have been associated with cancer development. HCgp-39 shares high sequence(More)
Glucansucrases are extracellular enzymes that synthesize a wide variety of α-glucan polymers and oligosaccharides, such as dextran. These carbohydrates have found numerous applications in food and health industries, and can be used as pure compounds or even be produced in situ by generally regarded as safe (GRAS) lactic acid bacteria in food applications.(More)
Glucansucrases are large enzymes belonging to glycoside hydrolase family 70, which catalyze the cleavage of sucrose into fructose and glucose, with the concomitant transfer of the glucose residue to a growing α-glucan polymer. Among others, plaque-forming oral bacteria secrete these enzymes to produce α-glucans, which facilitate the adhesion of the bacteria(More)
Branching enzyme (EC 2.4.1.18; glycogen branching enzyme; GBE) catalyzes the formation of α1,6-branching points in glycogen. Until recently it was believed that all GBEs belong to glycoside hydrolase family 13 (GH13). Here we describe the cloning and expression of the Thermus thermophilus family GH57-type GBE and report its biochemical properties and(More)
Quercetin 2,3-dioxygenase is a copper-containing enzyme that catalyzes the insertion of molecular oxygen into polyphenolic flavonols. Dioxygenation catalyzed by iron-containing enzymes has been studied extensively, but dioxygenases employing other metal cofactors are poorly understood. We determined the crystal structure of quercetin 2,3-dioxygenase at 1.6(More)
Flavodoxin II from Azotobacter vinelandii is a "long-chain" flavodoxin and has one of the lowest E1 midpoint potentials found within the flavodoxin family. To better understand the relationship between structural features and redox potentials, the oxidized form of the C69A mutant of this flavodoxin was crystallized and its three-dimensional structure(More)
The zinc-dependent leucine aminopeptidase from Pseudomonas putida (ppLAP) is an important enzyme for the industrial production of enantiomerically pure amino acids. To provide a better understanding of its structure-function relationships, the enzyme was studied by X-ray crystallography. Crystal structures of native ppLAP at pH 9.5 and pH 5.2, and in(More)
Fructansucrases (FSs) catalyze a transfructosylation reaction with sucrose as substrate to produce fructo-oligosaccharides and fructan polymers that contain either β-2,1 glycosidic linkages (inulin) or β-2,6 linkages (levan). Levan-synthesizing FSs (levansucrases) have been most extensively investigated, while detailed information on inulosucrases is(More)
ΔN(123)-glucan-binding domain-catalytic domain 2 (ΔN(123)-GBD-CD2) is a truncated form of the bifunctional glucansucrase DSR-E from Leuconostoc mesenteroides NRRL B-1299. It was constructed by rational truncation of GBD-CD2, which harbors the second catalytic domain of DSR-E. Like GBD-CD2, this variant displays α-(1→2) branching activity when incubated with(More)
Using the isolated perfused rat liver technique we examined whether the accumulation and sinusoidal efflux processes of the organic anion dibromosulfophthalein (DBSP) are dependent on the intracellular ATP content, chloride concentration in the perfusion medium as well as temperature of the medium and whether they are mediated by the same or by separate(More)