Zur Chemie des Blutfarbstoffes. 12. Mitteilung. Über die tryptische Verdauung des Blutfarbstoffes.

Abstract

Oxyhemoglobin, CO-hemo-globin, and reduced hemoglobin were hydrolyzed by pancreatic trypsin at nearly the same rate. This hydrolysis was inhibited by putrefaction enzyme action. Tryptic hydrolysis did not alter the prosthetic group. About 95% of the globin was split into dialyzable fractions and about 5% was transformed into new compounds. These amorphous heminproteoses could be precipitated as an impure mixture from the digest by acetic acid. The precipitate contained about 3.4-5.3% of bound Fe; that is, from 40-60% of it was hemin. The molecular weight of the heminproteoses was > 20,000; to this protein residue adhered a large number of proto-hemin residues. The protein components of heminproteoses were resistant to digestion with pepsin. The union between protein and hemin was very stable; it was broken only by long-continued boiling with concentrated HCl. A COOH group of the hemin molecule may be bound with an ester or peptid linkage to the protein molecule; the Fe is not involved in this linkage.