An improved colorimetric aldolase method in which the quantity of aldolase in a sample is determined by the rate at which it enzymatically cleaves fructose-1, 6-diphosphate (FDP) into glyceraldehyde-3-phosphate (GAP) and dihydroxyacetone phosphate (DHAP); the phosphate group is hydrolyzed from the GAP and DHAP; and one of the hydrolysis products is measured. The initial enzymatic reaction is carried out in a reaction mixture containing a concentrated tris-(hydroxymethyl)-aminomethane buffer, pH 7.0, and a small quantity of sodium fluoride, but without added hydrazine or other compound to prevent the enzymatic conversion of a great majority of GAP to DHAP in the reaction mixture. Hydrolysis of the reaction products and conversion to a colored reaction product is carried out by a procedure which yields intense, long-lasting, reproducible color. An improved standard includes dihydroxyacetone carried through the same procedure.
In a photochemical measurement methodof a trace enzyme which comprises: using a synthetic substrate bringing either the reaction product formed by enzyme reaction or the unreacted synthetic substrate into contact with silver halide, developing the same, and measuring optical density of the formed silver image and/or colored dye, the synthetic substrate comprises at least one structure (A) which is specifically contacted with an enzyme to be measured and at least one photographically fogging agent structure (B) in the molecule thereof.
Various embodiments provide, for example, buffer compositions and/or sieving formulations useful in connection with electrophoresis instruments, such as capillary electrophoresis (CE) devices. In various embodiments, a buffer composition can include Bis-Tris, TAPS and/or TAPSO, and, optionally, a chelating agent, such as EDTA. Methods of separating samples containing bio-molecules, such as DNA or RNA, are also described.
