Preparation and O2 binding study of myoglobin having a cobalt porphycene.
Sperm whale myoglobin, an oxygen-storage hemoprotein, was reconstituted with 2,7-diethyl-3,6,12,17-tetramethyl-13,16-bis(carboxyethyl)porphycenatocobalt(II) in order to investigate the reactivities of a cobalt porphycene in a protein matrix. Similar to the previously reported finding for the myoglobin with the iron porphycene, the reconstituted myoglobin with the cobalt porphycene was also found to have an O2 affinity 2 orders of magnitude greater than that of the myoglobin possessing cobalt protoporphyrin IX. The EPR spectra of the deoxy and oxy myoglobins having the cobalt porphycene at 77 K also have features similar to those of the myoglobin with cobalt protoporphyrin IX. These spectra suggest that the porphycene cobalt in the deoxy form is coordinated by one nitrogenous ligand postulated to be the imidazole ring of His93, and that the bond configuration of CoII-O2 is regarded as the CoIII-Omicron2*- species.
Matsuo
Takashi
T
Division of Applied Chemistry, Graduate School of Engineering, Osaka University, Suita, Osaka 565-0871, Japan.
Tsuruta
Takashi
T
Maehara
Keiko
K
Sato
Hideaki
H
Hisaeda
Yoshio
Y
Hayashi
Takashi
T
D003035:Cobalt / Q000737:chemistry*; D004578:Electron Spin Resonance Spectroscopy; D007700:Kinetics; D015394:Molecular Structure; D009211:Myoglobin / Q000737:chemistry*; D009942:Organometallic Compounds / Q000138:chemical synthesis* / Q000737:chemistry; D010100:Oxygen / Q000737:chemistry*; D011166:Porphyrins / Q000737:chemistry*; D013997:Time Factors
D009211:Myoglobin; D009942:Organometallic Compounds; D011166:Porphyrins; C051407:porphycene; D003035:Cobalt; D010100:Oxygen