Proteinase and alpha-amylase Inhibitors of Sweet Potato: Changes during growth Phase, Sprouting, and Wound Induced Alterations

甘藷中的蛋白本酶及α-澱粉酶抑制劑：在生長、發芽期間的變化及損傷所引起的改變

K. Sasikiran ； M. R. Rekha ； G. Padmaja

《Botanical Bulletin of Academia Sinica》 43卷4期 (2002/10) Pp. 291-298

https://doi.org/10.7016/BBAS.200210.0291

摘要

本研究在甘藷生長及發芽期間，監測蛋白酶（胰蛋白酶及凝乳胰蛋白酶）及α-澱粉酶抑制劑(AI)的變化，以證實這些植物萃取成分的生物性角色。雖然胰蛋白酶抑制劑(TI)的活性於栽種後(DAP)15天，在四種基因型的甘藷塊根成形期間非常的低，但根據觀察，在塊根體積變大的時期卻急劇上升，這顯示了該抑制劑在調節植物蛋白酶中，可能扮演著重要的角色。相反地，凝乳蛋白酶抑制劑(CI)活性，從栽種40-90天後即顯著降低，表示它在蛋白酶的調節上并不是很重要。在三種基因型甘藷的塊根體積增長起始期，α-澱粉酶抑制劑突然顯著增加，且於種植105天後，也就是塊根體積增長完成時期，活性突然明顯下降，所以從本研究的結果，可以闡明AI在調節甘藷內生性α-澱粉酶的角色。將塊根栽種在蛭石中直到第6天，TI活性持續增加，但芽冒出後即下降，顯示發芽期間蛋白質開始進行水解的可能性。AI活性則持續下降直到發芽，表示AI在甘藷中為氮儲存蛋白質。當組織受到損傷時，在四種基因型甘藷的葉中，蛋白酶抑制劑均有顯著的增加。且相較於受損葉片，在沒有受損傷的葉片中增加的更明顯。甘藷的蛋白酶及澱粉酶抑制劑及由傷害所引發的這個事實，表明了其主要扮演著一個防禦性的角色。因為甘藷常用來當作動物的飼料，所以，蛋白酶抵制劑在甘藷葉、藤蔓中的含量，以及在植物生長各階段的變化等更具意義。

關鍵字

α-澱粉酶抑制劑 ； 胰凝乳蛋白酶抑制劑 ； 生長期 ； 甘藷(Ipomoea batatas) ； 發芽 ； 胰蛋白酶抑制劑 ； 損傷

並列摘要

Changes in proteinase (trypsin and chymotrypsin) and α-amylase inhibitors were monitored during the growth phase and sprouting of sweet potato, with a view to establishing the biological role of these secondary plant principles. Although the trypsin inhibitor (TI) activity of tuberising roots of sweet potato was very low in four genotypes at 15 days after planting (DAP), a steep increase was observed during the tuber-hulking phase, indicating a possible role for the inhibitor in regulating plant proteinases. In contrast, the chymotrypsin inhibitor (CI) activity decreased from 40-90 DAP, indicating an inconsequential role in protease regulation. With initiation of tuber bulking, the α-amylase inhibitor (AI) increased sharply in three sweet potato genotypes, and after completion of the bulking phase, the activity came down sharply at 105 DAP. A pronounced role for regulation of endogenous a-amylases by the AI of sweet potato could be postulated from the study. The TI activity increased in the tubers until the sixth day of planting in vermiculite, and it decreased with the emergence of sprouts, indicating the possibility of proteolytic cleavage at the time of sprouting. Amylase inhibitor activity continuously decreased until sprouting, indicating the role of these proteins as N-reserve proteins in sweet potato. A significant increase in proteinase inhibitor levels in all the sweet potato leaves was observed within four hours of artificial wounding. The rise in inhibitor levels was more evident in leaves far off from the wounded leaf. The fact that proteinase and amylase inhibitors of sweet potato are wound-inducible points to a major defensive role for them. This information on the proteinase inhibitor levels in sweet potato leaves and vines and their change with plant growth is of interest, especially due to their use as animal feed.

並列關鍵字

α-Amylase inhibitor ； Chymotrypsin inhibitor ； Growth phase ； Ipomoeo batatos ； Sprouting ； Trypsin inhibitor ； Wounding