This invention relates to a new starch branching enzyme, and to the gene encoding the enzyme. In particular, the invention provides a new starch branching enzyme type II from wheat, the nucleic acid encoding the enzyme, and constructs comprising the nucleic acid. The invention also relates to a novel method for identification of branching enzyme type II proteins, which is useful for screening wheat germplasm for null or altered alleles of wheat branching enzyme IIb. The novel gene, protein and methods of the invention are useful in production of plants which produce grain with novel properties for food and industrial applications, for example wheat grain containing high amylose or low amylopectin starch.