Granule‐Bound Starch Synthase I (GBSSI) in Quinoa (Chenopodium quinoa Willd.) and Its Relationship to Amylose Content

• Published in: Cereal chemistry Vol. 82; no. 3; pp. 246 - 250
• Main Authors: Lindeboom, N., Chang, P. R., Tyler, R. T., Chibbar, R. N.
• Format: Journal Article
• Language: English
• Published: St. Paul, MN The American Association of Cereal Chemists, Inc 01-05-2005; American Association of Cereal Chemists
• Subjects: Biological and medical sciences; Cereal and baking product industries; Food industries; Fundamental and applied biological sciences. Psychology; Quinoa; Starch and starchy product industries; Starch granule; Quinoa; Amylose; Pseudocereals; Dicotyledones; Angiospermae; Spermatophyta; Polysaccharide; Chenopodiaceae; Chenopodium quinoa
• ISSN: 0009-0352; 1943-3638
• DOI: 10.1094/CC-82-0246

ABSTRACT
The amylose concentration in starch from 16 quinoa (Chenopodium quinoa Willd.) genotypes grown under identical conditions was 4–20%. Based on the amylose content, a selection of six genotypes was made. Starch granule‐bound proteins were extracted from six genotypes and analyzed using denaturing gel electrophoresis. Two major polypeptides with apparent molecular masses of 56 and 62 kDa were present in all genotypes. Both were identified as granule‐bound starch synthase I (GBSSI) using immunoblot analysis and internal peptide sequencing. The content of the two GBSSI isoforms in starch granules from the six genotypes, as determined by densiometry of the peptide bands, was positively correlated with the concentration of amylose in starch from mature seed. Starch synthase activity in developing seed was positively correlated to starch concentration in seed and amylose concentration in starch during seed development.