Limited proteolysis of myoglobin opens channel in ferrochelatase-globin complex for iron to zinc transmetallation

Author(s)

Paganelli, Marcella O. ^[1] ; Grossi, Alberto B. ^[2] ; Dores-Silva, Paulo R. ^[1] ; Borges, Julio C. ^[1] ; Cardoso, Daniel R. ^[1] ; Skibsted, Leif H. ^[2]

Affiliation

^[1] Univ Sao Paulo, Inst Quim Sao Carlos, Ave Trabalhador Sao Carlense 400, CP 780, BR-13560470 Sao Carlos, SP - Brazil

^[2] Univ Copenhagen, Dept Food Sci, Food Chem, Rolighedsvej 30, DK-1958 Frederiksberg C - Denmark

• Document type: Journal article
• Source: Food Chemistry; v. 210, p. 491-499, NOV 1 2016.
• Web of Science Citations: 7

Abstract

Recombinant ferrochelatase (BsFECH) from Bacillus subtilis expressed in Escherichia coli BL21(DE3) was found by UV-visible spectroscopy to bind the model substrate tetraphenylporphyrin-sulfonate, TPPS, with K-a = 3.8 10(5) mol/L in aqueous phosphate buffer pH 5.7 at 30 degrees C, and to interact with metmyoglobin with K-a = 1.07 +/- 0.13 10(5) mol/L at 30 degrees C. The iron/zinc exchange in myoglobin occurring during maturation of Parma hams seems to depend on such substrate binding to BsFECH and was facilitated by limited pepsin proteolysis of myoglobin to open a reaction channel for metal exchange still with BsFECH associated to globin. BsFECH increased rate of zinc insertion in TPPS significantly and showed saturation kinetics with an apparent binding constant of Zn(II) to the {[}enzyme-TPPS] complex of 1.3 10(4) mol/L and a first-order rate constant of 6.6 10(-1) s(-1) for dissociation of the tertiary complex, a similar pattern was found for zinc/iron transmetallation in myoglobin. (C) 2016 Elsevier Ltd. All rights reserved. (AU)

• FAPESP's process: 11/51555-7 - Bread and meat for the future
• Grantee: Daniel Rodrigues Cardoso
• Support Opportunities: Regular Research Grants