A comparative study of protoheme and heme d catalases : role of the heme and the heme pocket in catalysis and ligand binding

Catalase dismutes H20 2 to O2 and H20. In successive twoelectron reactions H20 2 induces both oxidation and reduction at the heme group. In the first step the protoheme prosthetic group of beef liver catalase forms compound I, in which the heme has been oxidized from Fe3+ to Fe4+=0 and a porphyrin radical has been created. Compound II is formed by the oneelectron reduction of comp I. It retains Fe4+=0 but lacks the porphyrin radical and is catalytically inert. Molecular structures are available for Escherichia coli Hydroperoxidase II, Micrococcus Iysodeiktus, Penicillium vitale and beef liver enzymes, which contain different hemes and heme pockets. In the present work, the pockets and substrate access channels of protoheme (beef liver & Micrococcus) and heme d (HPII of E. coli and Penicillium) catalases have been analysed using Quanta™ and CharmMTM molecular modeling packages on the Silicon Graphics Iris Indigo 2 computer. Experimental studies have been carried out with two catalases, HPII (and its mutants) and beef liver. Fluoride and formate' are inhibitors of both enzymes, and their binding is modulated by the heme and by distal residues N201 & H128. Both HPII and beef liver enzymes form compound I with H202 or peracetate. The reduction of beef liver enzyme compound I to II and the decay of compound II are accelerated by fluoride. The decay of compound II is also accelerated by formate, and this reagent acts as a 2-electron donor towards compound I of both enzymes. It is concluded that heme d enzymes (Penicillium and HPII of E. coli) are formed by autocatalytic transformation of protoheme in a modified pocket which contains a characteristic serine residue as well as a partially occluded heme channel. They are less active than protoheme enzymes but also do not form the inactive compound II species. Binding of peroxide as well as fluoride and formate is prevented by mutation of H128 and modulated by mutation of N201.

Indenture between Margaret Clifford and Samuel D. Woodruff

Indenture of deed of land between Margaret Clifford of Grantham and Samuel D. Woodruff of St. Catharines for lots 12 and 13 in the 8th Concession in the Township of Grantham. This was registered February 7, 1872 - instrument no. 19112 [?], February 2, 1872.

Invitation: Gala Concert in honour of Her Majesty Queen Elizabeth and His Royal Highness the Duke of Edinburgh

An invitation from The Right Honourable Pierre Elliott Trudeau for a gala concert in the Opera of the National Arts Centre in honour of Her Majesty Queen Elizabeth and His Royal Highness the Duke of Edinburgh.

I.O.D.E. Duke of Kent Chapter Fonds, 1934-1980

The I.O.D.E. as we currently know it today was founded in 1900 by Margaret Polson Murray of Montreal, who recognized a need for loyal support of Canadians departing to fight in the Boer War with the Empire forces in South Africa. She encouraged the formation of a federation of women to promote patriotism, loyalty and service to others. The first chapter was formed in Fredericton, New Brunswick on January 15th 1900. Primary chapters were formed in quick succession across Canada. In 1901, Edith Boulton Nordheimer was elected the first national president, the location of the head office became Toronto, Ontario and the federation was incorporated as Imperial Order Daughters of the Empire and Children of the Empire Junior Branch. The Duke of Kent Chapter was formed in 1934 and was disbanded in 1980. During the 1970’s the name I.O.D.E. was officially adopted. It is a federally chartered not-for-profit, charitable organization. Structured to report under the jurisdiction of the National chapter are the Provincial chapters, the Municipal chapters and the Primary chapters. The I.O.D.E. is associated with the Victory League in England and Daughters of the British Empire in the United States and it is proud of its heritage and traditions. Queen Elizabeth II is the current patron of the organization and although chapters sometimes disband there are always new chapters forming, including e-chapters that meet through 21st century electronics.