Chromogenic tests in the presence of cells

Abstract

The present invention concerns a method for the colorimetric measurement of enzyme activities comprising the following steps: preparing a cell suspension or a cell lysate containing cell components adding a chromogenic substrate at the start of the enzyme reaction adding a first additional substance to stop the enzyme reaction colorimetric measurement wherein a second additional substance which reduces the light scattering and/or absorption caused by the cells or the cell components is added during or after termination of the enzyme reaction.

1 . A method for colorimetric measurement of an enzyme reaction comprising the steps of: 
 preparing a cell suspension or a cell lysate comprising cell components,    adding a chromogenic substrate at the start of the enzyme reaction,    adding a substance which reduces light scattering and/or absorption caused by the cells or the cell components,    adding a reagent to stop the enzyme reaction, and    conduction a colorimetric measurement wherein said substance is added before, during or after termination of the enzyme reaction.    
   
   
       2 . The method according to  claim 1  wherein said substance adjusts the refractive index of the cell suspension to that of the cells, or said substance adjusts the refractive index of the cell lysate to that of the cell components.  
   
   
       3 . The method according to  claim 1  wherein said substance removes water from the cells or cell components due to its molar concentration and by means of osmotic pressure.  
   
   
       4 . The method according to  claim 1  wherein said substance dissolves a membrane of the cell.  
   
   
       5 . The method according to  claim 4  wherein said substance is a protein or a peptide.  
   
   
       6 . The method according to  claim 4  wherein said substance is a detergent.  
   
   
       7 . A kit for colorimetric measurement of an enzyme reaction in a cell suspension or cell lysate containing cell components, the kit comprising: 
 a chromogenic substrate,    a substance which, when added to the cell suspension or cell lysate, reduces light scattering and/or absorption caused by the cells or the cell components, and    a reagent to stop the enzyme reaction.    
   
   
       8 . The kit according to  claim 7  wherein said substance adjusts the refractive index of the cell suspension or cell lysate to that of the cells or cell components.  
   
   
       9 . The kit according to  claim 7  wherein said substance dissolves a membrane of the cell.