Neu1^b

Sequencing of the b allele revealed 5 nucleotide differences compared to the a allele. These changes alter the amino acid residues 11, 15, 17, 19 and 209 of the encoded protein from Arg, Cys, Val, Cys and Ile to Gly, Tyr, Ala, Arg and Leu, respectively. This encoded protein has greater activity than the protein encoded by the b allele as demonstrated in an in vitro assay. Further studies attributed most of the activity difference to the variation at position 209. (J:43930)