Center for Molecular Modeling - C. Van de Wiele

Analytical characterization of NOTA-modified somatropins

wim — Thu, 03 Apr 2014 12:08:25 +0000

N. Bracke, E. Wynendaele, M. D'Hondt, R. Haselberg, G.W. Somsen, E. Pauwels, C. Van de Wiele, B. De Spiegeleer

Journal of Pharmaceutical and Biomedical Analysis

96, 1–9

2014

Abstract

Chemical modification of biomolecules like the introduction of metal-chelators into proteins can lead to heterogeneous product formation. The nature and extend of the modification is important in interpreting the biological properties of the bioconjugate, given their possible influence on the pharmacokinetics as well as on the binding affinity to the target. The present study describes the synthesis and analytical characterization of somatropin modified on its lysine's ɛ-amino groups with the acylating chelator S-2-(4-isothiocyanatobenzyl)-1,4,7-triazacyclononane-1,4,7-triacetic acid (p-SCN-Bn-NOTA). Direct separation and identification techniques (i.e. RP-MS and CE-MS) and peptide mapping after trypsin and chymotrypsin digestion demonstrated that the use of higher amounts of p-SCN-Bn-NOTA during synthesis leads to a complex product composition with higher order substitution degrees (i.e. multiple NOTA-moieties per somatropin molecule), as well as the presence of different position isomers. From the nine lysine (Lys) residues in somatropin, Lys-70 was experimentally found to be the modification hotspot under our synthesis conditions (pH = 9.0). This was supported by the in silico calculated lowest pKa value of 8.3 for Lys-70. Based on the crystal structure of somatropin in complex with the extracellular parts of the growth hormone receptor, the Lys-70 residue is positioned outside the binding pockets and will therefore not directly interfere with receptor binding. Gallium chelation by NOTA-somatropin resulted in a 100% complexation. The synthesis of NOTA-somatropin using p-SCN-Bn-NOTA and somatropin under our operational conditions is therefore a suitable synthesis procedure for the production of a target-specific radiopharmaceutical for further investigation towards treatment and visualization of growth hormone-specific cancers.

DOI

http://dx.doi.org/10.1016/j.jpba.2014.03.014

Private attachment

14_j_pharma_bio_analysis_xxxx_Bracke.pdf

In vitro metabolic stability of iodinated obestatin peptides

wim — Tue, 05 Feb 2013 12:14:36 +0000

B. De Spiegeleer, S. Van Dorpe, V. Vergote, E. Wynendaele, E. Pauwels, C. Van de Wiele, J.E. Garcıa-Ramos, J.C. Solis-Sainz

Peptides

33 (2), 272-278

2012

Abstract

Natriuretic peptides are endogenous hormones released by the heart in response to myocardial stretch and overload. While atrial and brain natriuretic peptides (ANP, BNP) were immediately considered cardiac hormones and their role was well-characterized and defined in predicting risk in cardiovascular disease, evidence indicating the role of C-type natriuretic peptide (CNP) in cardiovascular regulation was slow to emerge until about 8 years ago. Since then, considerable literature on CNP and the cardiovascular system has been published; the aim of this review is to examine current literature relating to CNP and cardiovascular disease, in particular its role in heart failure (HF) and myocardial infarction (MI). This review retraces the fundamental steps in research that led understanding the role of CNP in HF and MI; from increased CNP mRNA expression and plasmatic concentrations in humans and in animal models, to detection of CNP expression in cardiomyocytes, to its evaluation in human leukocytes. The traditional view of CNP as an endothelial peptide has been surpassed by the results of many studies published in recent years, and while its physiological role is still under investigation, information is now available regarding its contribution to cardiovascular function. Taken together, these observations suggest that CNP and its specific receptor, NPR-B, can play a very important role in regulating cardiac hypertrophy and remodeling, indicating NPR-B as a new potential drug target for the treatment of cardiovascular disease.

Open Access version available at UGent repository

DOI

http://dx.doi.org/10.1016/j.peptides.2012.12.010

Private attachment

12_Peptides_33(2)272_DeSpiegeleer.pdf

HPLC-MS characterisation of chelate modified somatropin

wim — Mon, 17 Oct 2011 14:06:31 +0000

E. Wynendaele, E. Pauwels, S. Van Dorpe, V. Vergote, C. Van de Wiele, B. De Spiegeleer

Poster

Conference / event / venue

10th Flemish youth conference of chemistry

Blankenberge, Belgium

Monday, 1 March, 2010 to Tuesday, 2 March, 2010

Abstract

2010_VJC_Evelien.pdf

LC-MS characterization and cell-binding properties of chelate modified somatropin

wim — Mon, 17 Oct 2011 13:27:33 +0000

E. Wynendaele, K. Mertens, E. Pauwels, C. Van de Wiele, B. De Spiegeleer

Poster

Conference / event / venue

International Symposium on Drug Analysis

Antwerp, Belgium

Tuesday, 21 September, 2010 to Friday, 24 September, 2010

Abstract

2010_VJC_Evelien.pdf

Classification of quorum-sensing peptides

wim — Fri, 26 Aug 2011 13:08:30 +0000

E. Wynendaele, E. Pauwels, C. Van de Wiele, A. Bronselaer, G. De Tre, B. De Spiegeleer

http://archive.ugent.be/record/1223747

Talk

Conference / event / venue

15de forum der Farmaceutische Wetenschappen

Spa, Belgium

Thursday, 12 May, 2011 to Friday, 13 May, 2011

Abstract (private)

2011-238c_Presentatie_FFW__Classification_of_QS_peptides_.pdf