Association of iron-protoporphyrin-IX (hemin) with myosins.
Addition of myosins isolated from guinea pig heart and rabbit skeletal muscle to hemin solutions resulted in the appearance of new absorption spectra indicating association of hemin and the myosins. Binding stoichiometry based on absorption changes was found to be two hemin sites per myosin molecule. The binding constants calculated from quenching of the intrinsic fluorescence of the myosins by hemin are Ka = 7 (+/- 2) 10(6) M-1 for skeletal muscle myosin, and Ka = 3 (+/- 1) x 10(7) M-1 for heart muscle myosin. Based on these findings, myosins are suggested as potential transporters of free hemin between cell organelles.
Bhoite-Solomon
V
V
Sackler Institute of Molecular Medicine, Tel Aviv University Sackler School of Medicine, Petah Tikva, Israel.
Kessler-Icekson
G
G
Shaklai
N
N
D000818:Animals; D001665:Binding Sites; D001692:Biological Transport; D006168:Guinea Pigs; D006418:Heme / Q000031:analogs & derivatives*; D006427:Hemin / Q000378:metabolism*; D066298:In Vitro Techniques; D009206:Myocardium / Q000378:metabolism; D009218:Myosins / Q000378:metabolism*; D011485:Protein Binding; D011817:Rabbits; D013050:Spectrometry, Fluorescence; D013057:Spectrum Analysis
D006418:Heme; D006427:Hemin; D009218:Myosins