Title, Preface, Content, List of authors

Abstract

Glycoproteins (i.e. proteins containing covalently bound carbohydrate) are ubiquitous constituents of all living organisms including bacteria. The posttranslational modification of polypeptides with carbohydrate groups is very commonforsecretory as well as integral membrane proteins of higher organisms which may function as enzymes, antibodies, hormones, structural or carrier proteins and receptors. Overthe past two decades theprincipal biosynthetic pathwaysleadingto thefinal carbohydrate structures of glycoproteins have been elucidated. The introduction of improved techniquessuchas high-resolution NMRandfast atom bombardment mass spectrometryas well as the introduction of novel chromatographic techniques for oligosaccharides over the past decade have expanded our knowledge of the enormous microheterogeneity of oligosaccharide structures that can be present at even a single glycosylation domain. The biological significance ofthis structural diversity seen in glycoproteinsis unclear. Recombinant DNAtechnology has permitted the efficient production of manybiologically important glycoproteins (membranereceptorsas well as their ligands) by expressionin heterologous mammaliancell lines. By using defined glycosylation mutantcell lines as hosts as have been derived from CHOand BHKcells (see paper byP. Stanley, this volume)it should be possible to obtain pure glycoproteinsof defined carbohydratestructures. Thestudyof the biological functionality of these glycosylation formswill considerably increase our understanding of the role of protein linked oligosaccharides. Pharmaceutical companies’ interest in the productionof clinically important humanproteins (many of which are glycoproteins) by biotechnological means, will undoubtedly have an impact on the developmentof glycoprotein biochemistry in the near future. The efforts of the pharmaceutical industry are directed toward human medicine, and manyclinically useful glycoproteins (immune-modulators, differentiation factors, glycoprotein hormones and receptors) are now available from recombinant sources. They shouldbe usedto develop our understandingofbiological phenomenaassociated with protein linked carbohydrates. However, only a multidisciplinary approachincluding molecular structure research, computer graphic model building as well as genetic engineering andcell biologyis likely to be successful. The present volume evolved from a workshopheld at the GBF in Braunschweigin June 1990 with the aim ofbringing together a balanced mixture of people from university settings whose interest runsfrom basicscience to the possible practical application of their research, i.e. including researchers from industrial laboratories with strong biotechnological interest. I thank the GBF administration, especially Sabine Peters, for help in running the workshop. Myspecial thank goesto all speakers, chairpersons and contributors to the book. The professionalhelp of Dr. J.-H. Walsdorff in editing this volumeis gratefully acknowledged.