Asian Science Citation Index is committed to provide an authoritative, trusted and significant information by the coverage of the most important and influential journals to meet the needs of the global scientific community.  
ASCI Database
308-Lasani Town,
Sargodha Road,
Faisalabad, Pakistan
Fax: +92-41-8815544
Contact Via Web
Suggest a Journal
 
Articles by K. Inouye
Total Records ( 2 ) for K. Inouye
  K Kojima , S Tsuzuki , T Fushiki and K. Inouye
 

Matriptase is a type II transmembrane serine protease containing the non-catalytic domains (stem domain) and catalytic domain in the extra-cellular region. Our aim is to address the role of the stem domain in the interaction between matriptase and its physiological inhibitor, hepatocyte growth factor activator inhibitor type I (HAI-1). We prepared secreted variants of recombinant matriptase containing the entire extra-cellular domain (HL-matriptase) or only the catalytic domain (L-matriptase), and compared the inhibition activities of a cell membrane-anchored form of recombinant HAI-1 (maHAI-1) against the matriptase variants in the hydrolysis of peptidyl–4-methyl-coumaryl-7-amide (MCA) substrates. HL-matriptase and L-matriptase were inhibited by purified maHAI-1 with a similar extent when t-butyloxycarbonyl (Boc)-Gln-Ala-Arg-MCA (1) and acetyl-Lys-Thr-Lys-Gln-Leu-Arg-MCA (2) were used as substrates. However, HL-matriptase was inhibited more strongly than L-matriptase by maHAI-1 in the hydrolysis of Boc-[(2S)-2-amino-3-(benzyloxycarbonyl)propionyl]-Pro-Arg-MCA (3). These results show that the stem domain of matriptase facilitates the inhibitory interaction of this protease with maHAI-1 in the hydrolysis of substrate 3, although it has no effect in the hydrolysis of substrates 1 and 2. To our knowledge, this is the first evidence that the stem domain of matriptase can affect the interaction between this protease and HAI-1.

  Y Miyake , M Yasumoto , S Tsuzuki , T Fushiki and K. Inouye
 

Matriptase is a type II transmembrane serine protease. The activation (i.e. conversion of the single-chain pro-form to the disulphide-linked-two-chain active form) of this enzyme is known to occur via a mechanism requiring its catalytic triad. We reported previously that the activated enzyme was produced in the conditioned medium when full-length rat matriptase was expressed in monkey kidney COS-1 cells. The present study aimed to address when and where the matriptase activation occurs. COS-1 cells expressing matriptase were labelled with a membrane-impermeable biotin derivative and then solubilized with Triton. Both activated and non-activated matriptase molecules were detected in the avidin precipitants of Triton extracts, whereas only the non-activated molecules were detected in the flow-through fraction of avidin-precipitation procedure. Single-chain matriptase has been thought to have an inherent activity. Indeed, a secreted single-chain variant of recombinant matriptase bearing mutation at the activation-cleavage site was found to exhibit the activity in hydrolyzing a synthetic peptide substrate at pH 7.5. However, the variant had little activity at pH 5.5, as found in the lumen of post-Golgi secretory vesicles. Altogether, it is concluded that the activation of matriptase may occur when the enzyme reaches the cell surface.

 
 
 
Copyright   |   Desclaimer   |    Privacy Policy   |   Browsers   |   Accessibility