Protein profiling of water and alkali soluble cottonseed protein isolates

Authors: He, Zhongqi; Zhang, Dunhua; Cao, Heping

Submitted to: Scientific Reports
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 6/1/2018
Publication Date: 6/18/2018
Citation: He, Z., Zhang, D., Cao, H. 2018. Protein profiling of water and alkali soluble cottonseed protein isolates. Scientific Reports. 8:9036. https://doi.org/10.1038/s41598-018-27671-z.
DOI: https://doi.org/10.1038/s41598-018-27671-z

Interpretive Summary: Cotton is America’s number one value-added crop. Much of the cotton land area in the US is located in the southern and southeastern regions. Cottonseed proteins and other residual fractions have shown great potential as value-added industrial products and bio-active functional materials. In this work, water-soluble cottonseed proteins (CSPw) and alkali-soluble cottonseed proteins (CSPa) were sequentially extracted from defatted cottonseed meal, and their polypeptide profiles were determined and analyzed. There were total 70 polypeptides identified from the proteins of the two cottonseed preparations, with molecular weights ranging from 10 to 381 kDa. This work enriched the fundamental knowledge on cottonseed protein composition, and would help in better understanding of the functional and physicochemical properties of cottonseed protein and for enhancing its biotechnological utilization. Further exploration of the multiple and different sequence coverage of these cottonseed proteins may shed more light on the evolution, post-translational modification and isoform of cottonseed and other oilseed proteins.

Technical Abstract: Cottonseed proteins and other residual fractions have shown great potential as value-added industrial products and bio-active functional materials. In this work, water-soluble cottonseed proteins (CSPw) and alkali-soluble cottonseed proteins (CSPa) were sequentially extracted from defatted cottonseed meal. Proteins of the two fractions were separated by 4-20% gradient polyacrylamide gel electrophoresis; individual bands were then excised from the gel and subjected to mass spectrometric analysis. There were total 70 polypeptides identified from the proteins of the two cottonseed preparations, with molecular weights ranging from 10 to 381 kDa. Putative functions of these proteins include storage, transcription/translation, synthesis, energy metabolism, antimicrobial activity, and embryogenesis. Among the most abundant are legumin A (58 kDa), legumin B (59 kDa), vicilin C72 (70 kDa), vicilin GC72-A (71 kDa), and vicilin-like antimicrobial peptides (62 kDa). This work enriched the fundamental knowledge on cottonseed protein composition, and would help in better understanding of the functional and physicochemical properties of cottonseed protein and for enhancing its biotechnological utilization.