Assay

A spectrophotometric assay for detecting hemoglobin degradation which comprises:

• a) preparing a mixture comprising hemoglobin and a proenzyme of a hemoglobin-degrading enzyme, wherein the mixture has a pH in the range from 7.5 to 7.6,
• b) measuring the absorbance of the mixture at a wavelength (λ) in the range from 404 to 407 nm,
• c) acidifying the mixture to activate the hemoglobin-degrading enzyme,
• d) incubating the mixture of step c),
• e) measuring the absorbance of the mixture of step d) at a wavelength (λ) in the range from 404 to 407 nm,
• f) adding a base to the mixture of step e) to effect renaturation of undegraded hemoglobin,
• g) incubating the mixture of step f), and
• h) measuring the absorbance of the mixture of step g) at a wavelength (λ) in the range from 404 to 407 nm.