INFORMATION CAPACITY OF THE CARBOHYDRATE CODE

Capacity for information in biological molecules is traditionally thou ght to reside in the primary sequence of proteins and RNA, recorded in the DNA. With the exception of some RNA molecules, proteins, if not s tructural, carry their information in binding sites for substrates of reactions, or in binding sites for control molecules. Some proteins bi nd to complex carbohydrates in a carbohydrate-specific fashion, includ ing enzymes, lectins and antibodies. These carbohydrates, assembled by sequential glycosyl transferases, also carry biological information, the other side of which is a binding protein that recognizes a specifi c sugar monosaccharides, sequence, anomerity, linkage, ring size, bran ching and substitution. It is the latter 7 parameters, however, that g ive carbohydrates a very large potential for information-carrying capa city in a short sequence. An exponentially growing body of knowledge e xists in this aspect of carbohydrate function.