1. Department of Biochemistry, Albert Einstein College of Medicine, 1300 Morris Park Avenue, Bronx, New York 10461, Department of Chemistry, Columbia University, New York, 10027, Departmento de Biologia Molecular e Biotecnologia, Universidade Federal do Rio Grande do Sul, Porto Alegre-RS 91501-970 Brazil, Department of Biochemistry and Fels Research Institute, Temple University School of Medicine, Philadelphia Pa 19140, and Carbohydrate Chemistry Team, Industrial Research Limited, Lower Hutt, New Zealand