Method for determination of components

In a method for determination of amylase activity in a biological sample, which comprises the steps of:

• (1) mixing the sample with NAD(P), phosphate, maltose phosphorylase, .beta.-phosphoglucomutase, glucose-6-P-dehydrogenase and at least one of glucose-1,6-diphosphate or fructose-1,6-diphosphate to form a first reaction solution;
• (2) subjecting the first reaction solution to reaction with maltopentose to form a second reaction solution;
• and
• (3) measuring the absorption of the second reaction solution at 340 nm, the improvement comprising:
• carrying out the reaction of the step (1) at 25.degree. to 50.degree. C. at pH 6 to 9 in the presence of glutathione reductase and glutathione of oxidation type;
• and
• carrying out the reaction of step (2) at 25.degree. to 50.degree. C. at pH 6 to 9 in the presence of dithiothreitol, .gamma.-glutamyl transpeptidase and glycylglycine.

A method for quantitatively determining NAD(P)H comprising the steps of:

• (a) oxidizing a sample using oxidized glutathione and glutathione reductase;
• (b) decomposing the oxidized glutathione remaining in the sample using .gamma.-glutamyl transpeptidase at 25.degree. to 50.degree. C. at pH 6 to 9 in the presence of glycine, glycylglycine or an equivalent thereof;
• (c) forming NAD(P)H in a reaction using a component present in the sample;
• (d) quantitatively determining any NAD(P)H formed in said reaction;
• and
• (e) correlating the amount of component present in the sample from the amount of NAD(P)H determined in step (d).