van't Hof W, Blankenvoorde M F, Veerman E C, Amerongen A V
Department of Oral Biochemistry, Academic Centre for Dentistry Amsterdam, 1081 BT Amsterdam, The Netherlands.
J Biol Chem. 1997 Jan 17;272(3):1837-41. doi: 10.1074/jbc.272.3.1837.
The lipocalins make up a heterogeneous superfamily of proteins. Although showing almost no sequence homology, they share very similar secondary and tertiary structures. Their ability to bind hydrophobic ligands is well established, but the physiological function of most lipocalins remains unclear. The lipocalin from the human Von Ebner's Gland of the tongue (VEGh) contains three sequence motifs corresponding with the papain-binding domains of cystatins, a family of naturally occurring cysteine proteinase inhibitors. We found that VEGh inhibited papain activity to a similar extent as salivary cystatin S. Furthermore, synthetic peptides derived from VEGh and cystatin C, comprising these three motifs, inhibited papain, too. We conclude that VEGh is a physiological inhibitor of cysteine proteinases and therefore can play a role in the control of inflammatory processes in oral and ocular tissues.
脂质运载蛋白构成了一个异质性的蛋白质超家族。尽管它们几乎没有序列同源性，但却具有非常相似的二级和三级结构。它们结合疏水配体的能力已得到充分证实，但大多数脂质运载蛋白的生理功能仍不清楚。来自人类舌部冯·埃布纳腺（VEGh）的脂质运载蛋白包含三个与半胱氨酸蛋白酶抑制剂（一类天然存在的半胱氨酸蛋白酶抑制剂家族）的木瓜蛋白酶结合结构域相对应的序列基序。我们发现，VEGh对木瓜蛋白酶活性的抑制程度与唾液半胱氨酸蛋白酶抑制剂S相似。此外，源自VEGh和半胱氨酸蛋白酶抑制剂C的包含这三个基序的合成肽也能抑制木瓜蛋白酶。我们得出结论，VEGh是半胱氨酸蛋白酶的一种生理抑制剂，因此可在口腔和眼部组织炎症过程的控制中发挥作用。
