期刊名称：Proceedings of the National Academy of Sciences
印刷版ISSN：0027-8424
电子版ISSN：1091-6490
出版年度：1991
卷号：88
期号：3
页码：882-886
DOI：10.1073/pnas.88.3.882
语种：English
出版社：The National Academy of Sciences of the United States of America
摘要：Slow heme transfer from horseradish peroxidases C2 and A2, cytochrome c peroxidase, chloroperoxidase, and leghemoglobins to a heme acceptor protein, apomyoglobin, has been studied under mild conditions. The reaction is best described as heme release into water followed by quick engulfment by apomyoglobin. The energetics of the activated process are large and interpreted as connected to both polypeptide motions during release and the ordering of water around the heme during solvation. The free energy required to break the iron(III)-ligand 5 (L5) bond is a minor but crucial portion of the activation free energy. Donor-acceptor protein interactions are not involved in the transfer. Fast heme release from inactive protein has also been observed. Apoprotein recombination with porphyrins and hemes suggest that this lack of activity is a result of Fe-L5 bond breaking.
