Hemoglobin enzymatic hydrolysis

Application and Principle This procedure is used to determine the proteolytic activity, expressed as hemoglobin units on the tyrosine basis (HUT), of preparations derived from Aspergillus oryzae var. and Aspergillus niger var., and it may be used to determine the activity of other proteases at pH 4.7. The test is based on the 30-min enzymatic hydrolysis of a hemoglobin substrate at pH 4.7 and 40°. Unhydrolyzed substrate is precipitated with trichloroacetic acid and removed by filtration. The quantity of solubilized hemoglobin in the filtrate is determined spectrophotometrically. 

The most studied example of substrate adsorption and its effect on bacterial activities is that of the entrance of proteins into the interlamellar space of montmorillonite to form complexes. Ensminger and Gieseking (1942) found that the enzymatic hydrolysis of albumen and hemoglobin was suppressed in the presence of montmorillonite but not in kaolinite. Many others have subsequently made similar observations. Proteins are not completely inaccessible to enzyme attack when present in the interlamellar regions of clays but the rate of decomposition is often markedly decreased. Some workers have reported that organic materials adsorbed on the surface of kaolinite are protected to some extent against decomposition others have observed little or no such effect. McLaren and... 

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