Activity Based Profiling of Carbohydrate Processing Enzymes

Today, Glycosciences are accepted as interdisciplinary research field bearing great potential for future achievements due to the eminent importance and strong impact of carbohydrates in chemistry, biology and medicine. In this respect, carbohydrate processing enzymes (CPEs), which are ubiquitous in living cells, play vital roles, not only in nutrition but also in the metabolism of carbohydrate structures inside as well as outside cells. A malfunction of CPEs causes aberration of the structure or function of glycoconjugates resulting in diseases such as diabetes, bacterial as well as viral infections, immunological diseases, cancer, lysosomal storage diseases and other human genetic disorders, to mention a few examples. Recently, it was assumed that the carbohydrate household may also play a crucial rule in the context of Alzheimers and Parkinson disease. However, and as a matter of fact, in many diseases the mode of action concerning the carbohydrate part is still unknown or even unrealised. This project aims at developing a novel concept for activity based protein profiling of CPEs by adapting the ligand-directed chemistry for protein labeling. By chemical approaches, glycomimetic (carbohydrate look-a-likes) based probes will be synthesised which will be biological evaluated with the respective proteins by our collaboration partners. Such probes can find application for the elucidation of unknown disease pathways. The innovative aspect and big advantage of this novel method is that the respective enzymes undergo labeling outside their active site leaving their activity towards natural substrates intact, which enables the real-time monitoring of enzyme activity in living cells. This technique is clearly seen to address unanswered questions in cellular biology as well as pharmaceutical and medicinal sciences. For example this method facilitates the detection and identification for developing strategies for the treatment of sometimes yet not curable carbohydrate related diseases in general and for designing and synthesising novel glycomimetic structures as potential therapeutics thereof. The elucidation of the role of carbohydrates and carbohydrate processing proteins in the living system will provide knowledge for chemistry, biology as well as - for the welfare of mankind - medicine.

Carbohydrate processing enzymes (CPEs) are ubiquitous in living cells thereby playing vital roles, not only in nutrition but also, and most importantly, in the carbohydrate metabolism of glycoconjugates inside as well as outside cells. A malfunction of CPEs causes aberration of the structure and/or function of glycoconjugates resulting in diseases such as diabetes, bacterial as well as viral infections, immunological diseases, cancer, lysosomal storage diseases. Recently, dysfunction in CPE activity has been reported to be related to Alzheimers and Parkinson disease. As a matter of fact, in many carbohydrate related diseases, the contribution and/or the role of the carbohydrate part is still unknown or even unrealized. In this respect, activity-based protein profiling (ABPP) has become a powerful strategy for studying and elucidating protein activity in their native environment. In this project we have developed a method for activity based protein profiling of carbohydrate processing enzymes which can elucidate details of the enzyme mechanism, active-site architecture, substrate/inhibitor selectivity of proteins within biological systems. The applications can be profiling enzyme activity in human cell lines, elucidating of infectious disease models, biochemical pathway discovery of cancer, diagnosis management as well as target identification and evaluation of enzyme inhibitors. This opens promising new research avenues in the field of glycosciences.