USDA-ARS, Southern Regional Research Center, New Orleans, LA, 70124, USA.
USDA-ARS, Aquatic Animal Health Research Unit, Auburn, AL, 36832, USA.
Sci Rep. 2021 Apr 28;11(1):9209. doi: 10.1038/s41598-021-88527-7.
In this work, we sequentially extracted water (CSPw)- and alkali (CSPa)-soluble protein fractions from glandless cottonseed. SDS-Gel electrophoresis separated CSPw and CSPa to 8 and 14 dominant polypeptide bands (110-10 kDa), respectively. Liquid chromatography-electrospray ionization-tandem mass spectrometry identified peptide fragments from 336 proteins. While the majority of peptides were identified as belonging to vicilin and legumin storage proteins, peptides from other functional and uncharacterized proteins were also detected. Based on the types (unique peptide count) and relative abundance (normalized total ion current) of the polypeptides detected by mass spectrometry, we found lower levels (abundance) and types of legumin isoforms, but higher levels and more fragments of vicilin-like antimicrobial peptides in glandless samples, compared to glanded samples. Differences in peptide fragment patterns of 2S albumin and oleosin were also observed between glandless and glanded protein samples. These differences might be due to the higher extraction recovery of proteins from glandless cottonseed as proteins from glanded cottonseed tend to be associated with gossypol, reducing extraction efficiency. This work enriches the fundamental knowledge of glandless cottonseed protein composition. For practical considerations, this peptide information will be helpful to allow better understanding of the functional and physicochemical properties of glandless cottonseed protein, and improving the potential for food or feed applications.
在这项工作中，我们从无腺体棉籽中依次提取了水（CSPw）和碱（CSPa）可溶性蛋白。SDS-凝胶电泳将 CSPw 和 CSPa 分离为 8 个和 14 个主要多肽带（110-10 kDa）。液相色谱-电喷雾串联质谱鉴定了来自 336 种蛋白质的肽片段。虽然大多数肽被鉴定为属于伴大豆球蛋白和豆球蛋白贮藏蛋白，但也检测到来自其他功能和未鉴定蛋白质的肽。基于质谱检测到的多肽的类型（独特肽计数）和相对丰度（归一化总离子流），我们发现无腺体样品中的豆球蛋白同工型水平（丰度）较低，但类vicilin 的抗菌肽水平较高，片段较多，而有腺体样品中的 legumin 同工型水平（丰度）较高，但类 vicilin 的抗菌肽水平较低。无腺体和有腺体蛋白样品中 2S 白蛋白和油体蛋白的肽片段模式也存在差异。这些差异可能是由于无腺体棉籽中蛋白质的提取回收率较高，而有腺体棉籽中的蛋白质往往与棉酚结合，降低了提取效率。这项工作丰富了无腺体棉籽蛋白组成的基础知识。从实际考虑，这些肽信息将有助于更好地理解无腺体棉籽蛋白的功能和物理化学性质，并提高其在食品或饲料应用中的潜力。
