Spectrophotometry of amyloid degrading activity in serum or tissue

A method for measuring amyloid A degrading activity in serum or tissue, comprising the steps of:

• forming a substrate comprising a quantity of Congo red bound to amyloid A;
• adding to the substrate a buffer solution, thereby forming a suspension;
• adding to the suspension a quantity of serum or tissue homogenate, thereby forming a reaction mixture;
• incubating the reaction mixture to form, by the action of amyloid degrading factors in the serum or tissue homogenate, reaction products comprising unreacted substrate, degraded amyloid A and a supernatant containing Congo red released into the supernatant from the degraded amyloid A;
• separating the unreacted substrate and the supernatant;
• spectrophotometrically measuring the quantity of Congo red released into the supernatant;
• and
• calculating the quantity of amyloid A degraded based on the quantity of Congo red released into the supernatant.

A method for quantitatively measuring amyloid A degrading activity in serum or tissue, comprising the steps of:

• forming a substrate comprising a quantity of Congo red bound to amyloid A;
• adding to the substrate a buffer solution, thereby forming a suspension;
• adding to the suspension a quantity of serum or tissue homogenate, thereby forming a reaction mixture;
• incubating the reaction mixture to form reaction products comprising unreacted substrate, degraded amyloid A and a supernatant containing Congo red released into the supernatant from the degraded amyloid A;
• adding to the reaction mixture a solution comprising NaCl and water;
• separating the unreacted substrate and the supernatant;
• spectrophotometrically measuring at about 505 nm the quantity of Congo red released into the supernatant;
• and
• calculating the quantity of amyloid A degraded based on the quantity of Congo red released into the supernatant.

A method for measuring amyloid degrading activity in serum or tissue, comprising the steps of:

• forming a composition comprising a quantity of Congo red bound to an amyloid;
• adding to the composition a quantity of serum or tissue homogenate, thereby forming a reaction mixture;
• incubating the reaction mixture to allow amyloid degrading factors present in the serum or tissue homogenate to react with the amyloid component of the composition causing a portion of the amyloid to be degraded and the Congo red bound to the degraded amyloid portion to be released;
• separating an unreacted portion of the composition and a supernatant containing the Congo red released into the supernatant from the degraded amyloid portion;
• spectrophotometrically measuring the quantity of Congo red released into the supernatant;
• and
• calculating the quantity of the amyloid degraded based on the quantity of Congo red released into the supernatant.