Evaluation of drug-drug interaction between the novel cPLA2 inhibitor AK106-001616 and methotrexate in rheumatoid arthritis patients.

1. Drug interaction potential between AK106-001616, a novel cytosolic phospholipase A2 inhibitor, and methotrexate (MTX) in rheumatoid arthritis patients was investigated. This trial is registered with ClinicalTrials.

Contribution of cytochrome P450 and UDT-glucuronosyltransferase to the metabolism of drugs containing carboxylic acid groups: risk assessment of acylglucuronides using human hepatocytes.

1. In order to evaluate the inhibition activity of 1-aminobenzotriazole (ABT) and (-)-borneol (borneol) against cytochrome P450 (CYP) and UDP-glucuronosyltransferase (UGT), the substrates of these metabolic enzymes were incubated with ABT and borneol in human hepatocytes. We found that 3 mM ABT and 300 μM borneol were the most suitable experimental levels to specifically inhibit CYP and UGT.

A simple method to evaluate reactivity of acylglucuronides optimized for early stage drug discovery.

Drugs containing the carboxylic functional group can be metabolized to form acylglucuronides believed to cause idiosyncratic drug toxicity when the acylglucuronide is unstable. Recent studies have shown that the half-life of an acylglucuronide in phosphate buffer is the best means for classifying acylglucuronides into safe, warning, and withdrawn drugs. However, it is difficult to halt the late stage development of new chemical entities due to the instability of their acylglucuronides.

Chemo-enzymatic synthesis of eel calcitonin glycosylated at two sites with the same and different carbohydrate structures.

Naturally occurring glycopeptides and glycoproteins usually contain more than one glycosylation site, and the structure of the carbohydrate attached is often different from site to site. Therefore, synthetic methods for preparing peptides and proteins that are glycosylated at multiple sites, possibly with different carbohydrate structures, are needed. Here, we report a chemo-enzymatic approach for accomplishing this.

Chemo-enzymatic synthesis and structure-activity study of artificially N-glycosylated eel calcitonin derivatives with a complex type oligosaccharide.

Starting from N-glycosylated eel calcitonin derivatives that contain an N-acetyl-D-glucosamine residue specifically at the 3rd, 14th, 20th or 26th amino acid residue, corresponding glycopeptides with a complex-type oligosaccharide attached to the respective amino acid residue were synthesized by means of a transglycosylation reaction catalyzed by an endo-beta-N-acetylglucosaminidase from Mucor hiemalis . The use of a recombinant enzyme and an excess of a glycosyl donor led to a yield in excess of 60%. Calcitonin derivatives containing truncated oligosaccharides were also prepared via digestion of the complex-type N-glycan with exoglycosidases.

An NMR study of O-glycosylation induced structural changes in the alpha-helix of calcitonin.

We previously reported that two out of seven artificially O-glycosylated calcitonin derivatives had an altered peptide backbone conformation as indicated by decreased helical contents, determined by CD measurement. In the present study, two of those derivatives, in which a GalNAc residue is attached to Thr6 or Thr21 of calcitonin, were analyzed by NMR in order to determine the structural changes induced by the O-glycosylation in more detail. Deviations in the chemical shifts suggest that the structural change is not global but only a local one and is located in the vicinity of each O-glycosylation site.