Patent ID: 7482133

Claim:
An isolated beta (1,4)-galactosyltransferase I catalytic domain comprising SEQ ID NO: 5, wherein said catalytic domain catalyzes the formation of a glucose-beta(1,4)-N-acetylglucosamine bond at a greater rate than wild-type beta (1,4)-galactosyltransferase I catalytic domain, and wherein (a) the catalytic domain has a conservative amino acid exchange at amino acid position 228 of SEQ ID NO: 5, (b) the catalytic domain has a conservative amino acid exchange at amino acid position 229 of SEQ ID NO: 5, (c) the catalytic domain has conservative amino acid exchanges at amino acid positions 228 and 229 of SEQ ID NO: 5, (d) lysine is exchanged for arginine at amino acid position 228 of SEQ ID NO: 5, or (e) lysine is exchanged for arginine at amino acid position 228 and glycine is exchanged for alanine at amino acid position 229 of SEQ ID NO: 5, and wherein the rate of formation of the glucose-beta (1,4)-N-acetylglucosamine bond is at least two-fold greater, and wherein the wild-type .beta.(1,4)-galactosyltransferase I catalytic domain comprises FNRAKLL (SEQ ID NO: 1).