Abe M, Abe K, Kuroda M, Arai S
Laboratory for Food Science, Gakushuin Women's Junior College, Tokyo, Japan.
Eur J Biochem. 1992 Nov 1;209(3):933-7. doi: 10.1111/j.1432-1033.1992.tb17365.x.
A full-length cDNA clone for a cysteine proteinase inhibitor (cystatin) was isolated from a lambda gt10 cDNA library of immature corn kernels by screening with a mixture of cDNA inserts for oryzacystatins I and II. The cDNA clone spans 960 base pairs, encoding a 135-amino-acid protein containing a signal peptide fragment. The protein, named corn cystatin I, is considered to be a member of the cystatin superfamily, since it contains the commonly conserved Gln-Val-Val-Ala-Gly region that exists in most known cystatins as a probable binding site and is significantly similar to other cystatins in its overall amino acid sequence. Corn cystatin I expressed in Escherichia coli showed a strong papain-inhibitory activity. Northern blot analysis showed that the amount of mRNA for corn cystatin I reaches a maximum 2 weeks after flowering and then decreases gradually.
通过用水稻巯基蛋白酶抑制剂I和II的cDNA插入片段混合物进行筛选，从未成熟玉米粒的λgt10 cDNA文库中分离出一个半胱氨酸蛋白酶抑制剂（胱抑素）的全长cDNA克隆。该cDNA克隆跨度为960个碱基对，编码一个含有信号肽片段的135个氨基酸的蛋白质。该蛋白质被命名为玉米胱抑素I，被认为是胱抑素超家族的一员，因为它包含大多数已知胱抑素中常见的保守的Gln-Val-Val-Ala-Gly区域，该区域可能是一个结合位点，并且其整体氨基酸序列与其他胱抑素显著相似。在大肠杆菌中表达的玉米胱抑素I表现出很强的木瓜蛋白酶抑制活性。Northern印迹分析表明，玉米胱抑素I的mRNA量在开花后2周达到最大值，然后逐渐减少。
