<p> Pullulan is an unusual, industrially important polysaccharide in which short alpha-1,4 chains (maltotriose) are connected in alpha-1,6 linkages. Enzymes that cleave alpha-1,6 linkages in pullulan and release maltotriose are called pullulanases although pullulan itself may not be the natural substrate. In contrast, a glycogen debranching enzyme such GlgX, homologous to this family, can release glucose at alpha,1-6 linkages from glycogen first subjected to limit degradation by phosphorylase. Characterised members of this family include a surface-located pullulanase from <taxon tax_id="1313">Streptococcus pneumoniae</taxon> [<cite idref="PUB00015477"/>] and an extracellular bifunctional amylase/pullulanase with C-terminal pullulanase activity [<cite idref="PUB00015478"/>].</p> Pullulanase, extracellular