title: Preparation and O2 binding study of myoglobin having a cobalt porphycene.
abstract: 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.
authors.affiliation: Division of Applied Chemistry, Graduate School of Engineering, Osaka University, Suita, Osaka 565-0871, Japan.
authors.forename: Takashi
authors.initials: T
authors.lastname: Matsuo
authors.forename: Takashi
authors.initials: T
authors.lastname: Tsuruta
authors.forename: Keiko
authors.initials: K
authors.lastname: Maehara
authors.forename: Hideaki
authors.initials: H
authors.lastname: Sato
authors.forename: Yoshio
authors.initials: Y
authors.lastname: Hisaeda
authors.forename: Takashi
authors.initials: T
authors.lastname: Hayashi
mesh_terms: 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
chemical_list: D009211:Myoglobin; D009942:Organometallic Compounds; D011166:Porphyrins; C051407:porphycene; D003035:Cobalt; D010100:Oxygen