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.

Photograph of Mildred Sloman [n.d.]

Mildred Sloman is pictured with three unidentified gentlemen in this undated photograph, believed to be taken in London, Ontario. This black and white snapshot was in the possession of the Rick Bell family, whose ancestors include Black slaves from the United States.

Photograph of Josephine Sloman [n.d.]

Josephine Sloman pictured in this undated photograph taken in Niagara Falls. Josephine (Ellen Butler) Sloman was born in 1891 in London, Ontario. This small photo was among the family memorabilia in the possession of Rick Bell, of St. Catharines, whose ancestors include former Black slaves from the United States.

Small Cabinet Card of African American Man by John S. Thom, of Lucan, Ontario [n.d.]

A very small cabinet card type photograph of an unidentified man, possibly a relative of the Bell - Sloman family. A handwritten entry on the reverse of the photograph indicates it was taken by John S. Thom, of Lucan. No date is provided, however, John S. Thom is known to have been a photographer in Lucan from 1877-1882. This cabinet card was in the possession of Iris Sloman Bell, of St. Catharines. Relatives of the Sloman - Bell family include former African American slaves who settled in Canada.John S. Thom is listed as a photographer in Lucan, Ontario from 1877-1882. Aside from photography, he also operated a general store and sold notions. It appears he then moved to Sarnia, Ont. and is listed as a photographer there from 1882-1900. He is also recorded as being a Sarnia bicycle dealer. Source: Phillips, Glen C. The Ontario photographers list (1851-1900). Sarnia: Iron Gate Publishing Co., 1990.

Image of Niagara Falls n.d.

In 1818 Parkhurst Whitney built stairs leading to the river’s edge at Prospect Point. In 1825 Porter Brother replaced that staircase with a spiral one. In 1844 Whitney started a water powered incline railway there although the staircase was also used until 1890. In 1906 the water wheel was replaced by an electric power plant. There were lower buildings which included Shadow of the Rock which was a concession stand and also rented raincoats to the tourists. This was destroyed by fire and ice in 1892 and replaced by a chalet-style building in 1894-95. On July 6th, 1907 a cable on the incline railway broke. One person was killed and several sustained injuries. An elevator was constructed and it opened in January of 1910. It was condemned in 1954 when water entered the shaft, this was at the time of the collapse of Prospect Point which occurred at 4:50 pm. on July 28, 1954. This photograph was taken prior to 1954. Today the New York State Observation Tower stands at Prospect Point and The Maid of the Mist boat ride is available from the base of the tower. with information from: Niagara Falls Canada: a History by the Kiwanis Club of Stamford, Ontario

Photograph - Florence (wife of Francis Willson)

A photograph of Florence Upper, the wife of Francis Bond Head Willson.

Letter to Thomas Steers of Montreal from Samuel D. Woodruff

Letter to Thomas Steers of Montreal from Samuel D. Woodruff asking for information on the progress of the patent which will expire on the 16th of March, Feb. 9, 1848.

Indenture of Agreement for Sale of Land between S.D. Woodruff and Elizabeth Cudney

Indenture of agreement for Sale of Land between S.D. Woodruff of St. Catharines and Elizabeth Cudney of Willoughby regarding a footpath and Lots 9 and 10 in Willoughby, Feb. 6, 1893.

Certificate of exportation to S.D. Woodruff from Harnden Co. Stone

Certificate of exportation to S.D. Woodruff from Harnden Co. Stone for items sent to Lewiston from Buffalo. This is a handwritten 1 page document, Jan. 1, 1846[7].

Letter containing a list of accounts for S.D. Woodruff to accept or reject

Letter containing a list of accounts for S.D. Woodruff to accept or reject. This letter is slightly water damaged. This does not affect the text. It is signed by Jarvis, Conklin and Co., n.d.

Letter of notification to S.D. Woodruff from George H. Gillespie that a meeting of the Board of Directors has been called

Letter of notification to S.D. Woodruff from George H. Gillespie that a meeting of the Board of Directors has been called, Oct. 20, 1869.

Telegram from Great North Western Telegraph Company of Canada to S.D. Woodruff from L. Cabot

Telegram from Great North Western Telegraph Company of Canada to S.D. Woodruff from L. Cabot stating that he will take the shares, Jan. 16, 1886.

Telegram from Great North Western Telegraph Company of Canada to S.D. Woodruff from L. Cabot stating that the draft for $5000.00 will be forwarded

Telegram from Great North Western Telegraph Company of Canada to S.D. Woodruff from L. Cabot stating that the draft for $5000.00 will be forwarded on Monday or Tuesday, Jan. 16, 1886.

Estimate from the County of Welland to S.D. Woodruff for engineering services in marsh lands drainage for 1 year

Estimate from the County of Welland to S.D. Woodruff for engineering services in marsh lands drainage for 1 year, Dec. 1857.

Letter to S.D. Woodruff from an illegible signature stating that he suspects a clerical error in one of the columns, n.d.

Letter to S.D. Woodruff from an illegible signature stating that he suspects a clerical error in one of the columns, n.d.