花生种子贮藏蛋白的氨基酸组成分析及发育过程中17.5 kDa多肽的合成规律

COMPOSITION OF AMINO ACID IN STORAGE PROTEINS AND CHANGES IN 17.5 kDa POLYPEPTIDE SYNTHESIS DURING PEANUT SEED DEVELOPMENT

分析了两种不同蛋白质组成类型花生的子叶总蛋白３个主要组分及高甲硫氨酸类型花生的６０．５、４１、３８．５、１８和１７．５ ｋＤａ多肽的氨基酸组成，结果表明它们均含有 １７种氨基酸，其中天冬氨酸、谷氨酸和精氨酸含量最高，而甲硫氨酸含量和半胱氨酸水平都极低。高甲硫氨酸类型品种的各组分的甲硫氨酸含量均显著高于低甲硫氨酸类型品种的对应组分的甲硫氨酸含量，在这两种类型花生中伴花生球蛋白ＩＩ都是甲硫氨酸含量最高的组分。探讨了１７．５ ｋＤａ高甲硫氨酸多肽在花生种子发育过程中的合成规律。

Three major components of salt-soluble proteins in peanut seeds were roughly purified on Sephadex G-100 gel filtration. Five purified polypeptides, 60.5, 41, 38.5, 18 and 17.5 kDa polypeptides, were harvested with high purity and productivity. Amino acid composition of the three major components (arachin, conarachin I and conarachin II) and the five purified polypeptides were analyzed. It was shown that 17 amino acids, including 7 essential amino acids, were detectable. The contents of asparatic acid, glutamic acid and arginine were high, whereas methionine and cysteine were extremely low. The methionine levels of three major components in methionine-rich cultivar Shanyou 523 were obviously higher than those in cultivar Haihua 1. The methionine level of conarachin II in three major components was the highest in the two cultivars. Results showed that highest methionine in 17.5 kDa polypeptide was observed in the five purified polypeptides. Western blot showed synthetic changes in 17.5 kDa polypeptide during development of peanut seeds.