Melanin quantitation from XXXX erythrocytes; interference by haeme derivatives.

@entity1 @entity9203 @entity6188 @entity1425 @entity5828 @entity1063 @entity1068
Precipitates were obtained by 6 N @entity5828 hydrolysis of @entity1 erythrocytes and subsequent extractions with @entity1068 -ether 1:1 and with @entity6188 . The mean quantity of these precipitates (n = 16) was 16.60 +/- 1.60 (standard deviation) mg/ml, (15.09 +/- 1.45 mg/g) and from saline washed erythrocyte samples (n = 8) 16.65 +/- 0.73 mg/ml, (15.14 +/- 0.67 mg/g). A large part of these precipitates (about 74%) is associated with haemoglobin (in average 12.34 mg/ml). Melanins account for the difference (16.60-12.34) = 4.26 mg/ml, approximately 8.7% of haemoglobin-free erythrocyte solids. Precipitates from red cells, and from haemoglobin produced similar UV-VIS and IR spectra. The precipitates from haemoglobin are mainly derivatives of haeme (about 97%); the remaining approximately 3% are melanins from globin. The total melanins are about 1.3% of haeme-free solids of erythrocytes. Precipitation from the erythrocytes with 6 N @entity5828 was also achieved in practically complete argon atmosphere, and similar quantities were obtained as those in air with the same UV-VIS and IR spectra. Since granules or solid particles are not found in the cytoplasm of normal @entity1 erythrocytes, we conclude that soluble melanins are present. Small amounts of melanins can be present in the membranes as well, since the precursors of @entity9203 : @entity1063 , @entity1425 are present in these membranes.
