Chemistry Reference
In-Depth Information
protein synthesis, please see Table 4.1, for further application of neoglycoproteins
and examples of sugars as pharmaceuticals, please see Chapters 25 and 28 ).
What is presently covered by the umbrella term ' lectin ' is outlined throughout
this topic. As exemplarily emphasized in Table 15.1, intriguing clinical correlations
between the status of glycosylation and functional implications via lectins have
turned up (please see for example Chapters 25.2, 27 and 29). Moreover, the
molecular details of glycan recognition are unraveled inspiring drug design, and
new technologies for measuring lectin specifi city are being developed (please see
Chapters 13 and 14). Combined, these examples for dynamic research lines in
lectinology afford effi cient driving forces, to make sure that this fi eld maintains
its currently acquired prominent status, honored by a series of special feature
issues (please see bottom of Table 15.1), and its momentum.
15.5
Conclusions
The ability to agglutinate cells is common to different types of proteins. Respective
assays with erythrocytes led to an early convergence of work on antibodies and on
proteins from diverse sources that are not produced in response to an antigen. In
particular, the crucial role of certain hemagglutinins from plants and eel serum
in the process of defi ning the biochemical basis of the AB0 blood group epitopes
attest to their selectivity, rivaling that of antibodies. Close inspection of the litera-
ture teaches the lesson that this context entailed coining the term 'lectin'. It
embodies the aspect of molecular selectivity. At the same time, it separates the
agglutinins terminologically from immunoglobulins. As a consequence of the
haptenic inhibition of agglutination by sugars, 'lectin' is now the generic name
for carbohydrate- specifi c proteins, differing from (i) antibodies, (ii) enzymes acting
on the ligand and (iii) sugar sensor/transport proteins. The current wide scope of
structural and functional studies including promising medical perspectives,
described throughout this topic, ensures that lectinology will properly address the
challenges of deciphering the sugar code.
Summary Box
The discovery of nonantibody proteins with inherent selectivity rested on
observing agglutination of erythrocytes. The detection of AB0 blood- group -
selective activities different from immunoglobulins led to the introduction of
the term 'lectin' by W. C. Boyd in 1954. The current defi nition distinguishes
these carbohydrate-binding proteins from sugar- specifi c immunoglobulins,
enzymes acting on the ligand, and sensor/transport proteins for free mono-
and oligosaccharides.
