Sharief F S, Li S S
J Biol Chem. 1982 Dec 25;257(24):14753-9.
The low molecular weight, glutamine-rich storage protein isolated from the seeds of Ricinus communis (castor beans) has been shown to consist of two different polypeptide chains linked by disulfide bond(s). The small subunit is composed of 34 amino acids with a proline at its NH2 terminus, whereas the large subunit contains 61 amino acids with a cyclized glutamine as the NH2-terminal residue. The complete amino acid sequence of both subunits has been determined through characterization of the isolated subunits and selected peptides from trypsin, chymotrypsin, thermolysin, and cyanogen bromide cleavage. The intact protein possesses a large number of glutaminyl and half-cystinyl residues and exhibits sequence heterogeneity as observed from peptide sequences. Comparison of the sequence of this protein and those of other seed proteins indicates some structural similarities between them. The amino acid sequences of the two polypeptide chains of castor bean storage protein are: (formula, see text).
从蓖麻（蓖麻子）种子中分离出的低分子量、富含谷氨酰胺的贮藏蛋白已被证明由通过二硫键连接的两条不同多肽链组成。小亚基由34个氨基酸组成，其NH2末端有一个脯氨酸，而大亚基包含61个氨基酸，其NH2末端残基为环化谷氨酰胺。通过对分离的亚基以及来自胰蛋白酶、胰凝乳蛋白酶、嗜热菌蛋白酶和溴化氰裂解产生的选定肽段进行表征，已确定了两个亚基的完整氨基酸序列。完整的蛋白质含有大量的谷氨酰胺基和半胱氨酸残基，并且从肽序列观察到表现出序列异质性。将这种蛋白质的序列与其他种子蛋白的序列进行比较表明它们之间存在一些结构相似性。蓖麻贮藏蛋白两条多肽链的氨基酸序列如下：（分子式，见正文）
