2.4.1.18 amylopectin - 2.4.1.18 glycogen - 2.4.1.18 additional information each isoform of the Q-enzyme plays a distinct role in starch biosynthesis 2.4.1.18 additional information starch-branching enzyme and glycogen synthase work in a cyclically interdependent fashion 2.4.1.18 additional information differences in properties between isoforms of SBE are not the main factors that determine the polymodal distribution of branch lengths in amylopectin 2.4.1.18 additional information each branching enzyme isoform is involved in a different phase of glycogen synthesis 2.4.1.18 additional information the enzyme is responsible for the formation of the alpha-1,6 linkages in the glycogen molecule 2.4.1.18 additional information a fatal form of glycogen storage disease IV affects Norwegian Florest Cat, in which striated muscles and the nervous system are primarily affected, while the liver remains unaffected. This form of GSD IV is caused by a 6.1-kb deletion that eliminates exon 12 of the feline GBE1 gene 2.4.1.18 additional information glycogen branching enzyme GBE1 mutation causing equine glycogen storage disease IV.A C to A substitution at base 102 results in a tyrosine (Y) to stop (X) mutation in codon 34 of exon of exon 1. All 11 affected foals are homozygous for the X34 allele, all 16 control horses are homozygous for the Y34 allele. Poorly branched glycogen, abnormal polysaccharide accumulation, lack of measurable GBE1 enzyme activity and immunodetectable GBE1 protein, coupled with the present observation of abundant GBE1 mRNA in affected foals, are consistent with the nonsense mutation in the 699 amino acid GBE1 protein 2.4.1.18 additional information in absence of starch-branching enzyme IIb, the further absence of starch-branching enzyme Ia leads to increased branching