Jacob Kofoed

Discovery of the Once-Weekly Glucagon-Like Peptide-1 (GLP-1) Analogue Semaglutide.

Liraglutide is an acylated glucagon-like peptide-1 (GLP-1) analogue that binds to serum albumin in vivo and is approved for once-daily treatment of diabetes as well as obesity. The aim of the present studies was to design a once weekly GLP-1 analogue by increasing albumin affinity and secure full stability against metabolic degradation. The fatty acid moiety and the linking chemistry to GLP-1 were the key features to secure high albumin affinity and GLP-1 receptor (GLP-1R) potency and in obtaining a prolonged exposure and action of the GLP-1 analogue. Semaglutide was selected as the optimal once weekly candidate. Semaglutide has two amino acid substitutions compared to human GLP-1 (Aib(8), Arg(34)) and is derivatized at lysine 26. The GLP-1R affinity of semaglutide (0.38 ± 0.06 nM) was three-fold decreased compared to liraglutide, whereas the albumin affinity was increased. The plasma half-life was 46.1 h in mini-pigs following i.v. administration, and semaglutide has an MRT of 63.6 h after s.c. dosing to mini-pigs. Semaglutide is currently in phase 3 clinical testing.

Discovery of new peptide-Based catalysts for the direct asymmetric aldol reaction

A series of oligo-peptide based catalysts were prepared using Fmoc solid-phase peptide synthesis. It was found that peptides with N-terminal proline residues catalyzed an aldol reaction yielding enantiomeric enriched product. Peptide H-Pro-Glu-Leu-Phe-OH catalyzed the reaction with good activity and moderate enantioselectivity (66% ee). Furthermore, it was shown that an acidic side chain and/or C-termini are essential to catalysis.

Prebiotic carbohydrate synthesis: zinc–proline catalyzes direct aqueous aldol reactions of α-hydroxy aldehydes and ketones

Zn-proline catalyzed aldolisation of glycoladehyde gave mainly tetroses whereas in the cross-aldolisation of glycoladehyde and rac-glyceraldehyde, pentoses accounted for 60% of the sugars formed with 20% of ribose.

Zinc–proline catalyzed pathway for the formation of sugars

Zn-proline catalyzes the aldolisation of unprotected glycolaldehyde in water to give tetroses and hexoses; threose (33% of the product mixture) was formed with 10% enantiomeric excess of the D-isomer.

Comparing dendritic with linear esterase peptides by screening SPOT arrays for catalysis.

Fluorescence screening of a 96-membered SPOT library of histidine containing dendritic and linear peptides revealed the remarkable esterolytic activity of short histidine oligomers that show catalytic proficiencies within one order of magnitude of histidine-containing esterase peptide dendrimers.

Metabolism of peptide YY 3–36 in Göttingen mini-pig and rhesus monkey

Peptide YY 3-36-amide (PYY3-36) is a peptide hormone, which is known to decrease appetite and food-intake by activation of the Y2 receptor. The current studies were designed to identify the metabolites of PYY3-36 in mini-pig and rhesus monkey. Plasma samples were analyzed by high resolution LC-MS (and MS/MS) in order to unambiguously identify the metabolites of PYY3-36. In summary, the metabolism of PYY3-36 was similar in mini-pig and rhesus monkey. Several metabolites were identified and PYY3-34 was identified at the highest levels in plasma. In addition, mini-pigs were also dosed with PYY1-36-amide, PYY3-35, PYY3-34 and [N-methyl 34Q]-PYY3-36-amide in order to investigate the mechanisms by which PYY was metabolized. PYY3-35 was rapidly converted to PYY3-34 whereas dosing of PYY3-34 to mini-pigs only showed circulating degradation products at low levels, i.e., PYY3-34 was metabolically more stable than PYY3-36 and PYY3-35. [N-methyl 34Q]-PYY3-36-amide was hypothesized to be stable toward cleavage between 34Q and 35R and after i.v. administration to mini-pigs, one major cleavage product was identified as [N-methyl 34Q]-PYY3-35. Overall, this showed that cleavage between 35R and 36Y was possible as well as between 34Q and 35R (as shown for PYY3-35), which indicated that metabolism of PYY3-36 to PYY3-34 may be a two-step process. PYY1-36 was also dosed to mini-pigs, which showed that PYY1-36 was metabolized in the C-terminal as PYY3-36. The overall degradation pattern of PYY1-36 was more complex due to the simultaneous enzymatic degradation in the N-terminal to form PYY2-34/36 and PYY3-34/36. In vitro incubations with heparin stabilized plasma showed that PYY3-36 was degraded with a half-life of 175 min, whereas incubations with PYY3-35 (half-life of 6 min) showed a rapid formation of PYY3-34. In conclusion, the present studies showed that PYY3-36 underwent enzymatic degradation in the C-terminal part and that the major circulating metabolite was PYY3-34. Furthermore, it may be a sequential two-step process leading to the formation of PYY3-35 and subsequently the metabolically more stable PYY3-34.