Isolation of a thiol‐activated T‐kininogenase from the rat submandibular gland

FEBS Letters

Greenbaum, Lowell M.¹  Barlas, Aydin¹  Gao, Xiaoxing¹ 

[1] Department of Pharmacology and Toxicology and School of Graduate Studies, Medical College of Georgia, Augusta, GA 30912, USA

关键词: T-Kinin;    T-Kininogen;    T-Kininogenase;    Thiol activation;    Submandibular gland;    TLCK;    n-p-tosyl-L-lysine chloromethyl ketone;    PMSF;    phenylmethylsulfonyl fluoride;    DTT;    dithiothreitol;    HPLC;    high-performance liquid chromatography;    SBTI;    soybean trypsin inhibitor;    SDS-PAGE;    SDS-polyacrylamide gel electrophoresis;   

DOI  :  10.1016/0014-5793(87)81059-1

学科分类：生物化学/生物物理

来源: John Wiley & Sons Ltd.

【 摘 要 】

T-kininogenase (T-kgnase) activity has been investigated in tissues of the rat and submandibular glands of the rat, mouse and guinea pig. Both rat and mouse submandibular homogenates showed high T-kgnase activity. The enzyme has been purified 360-fold from rat submandibular gland homogenate supernatant fluid. The enzyme has an apparent molecular mass of 28 kDa and a pH optimum of 8.0 toward T-kininogen. It cleaved T-kininogen in catalytic quantities to release T-kinin (Ile-Ser-bradykinin) and small quantities of bradykinin and an unknown kinin. The activity of the enzyme was increased 10-fold in the presence of thiol groups (dithiothreitol) and inhibited by leupeptin (90%) and to a lesser extent by aprotinin (49%), TLCK (46%) and soybean trypsin inhibitor (27%). Pepstatin and PMSF did not inhibit the enzyme. Studies on substrate specificity, pH optimum and agents which inhibit T-kgnase activity demonstrate that this enzyme is different from plasma and tissue kallikreins, cathepsin D, esterase A and esterase B (other known kininogenases). It is the first thiol-activated kininogenase to be reported.

【 授权许可】

Unknown