Manganese proteins

Photosynthetic(II) chloroplasts, 2,773 Photosystem II dioxygen evolving centre manganese, 6, 586 manganese protein, 6, 590 Photothermography, 6, 118 Phthalamic acid, /V-(2-phenanthrolyl)-hydrolysis... 

The Mn111 acid phosphatases have an intense band in the visible spectrum at 515-570 nm, assigned to tyrosine-Mn111 charge transfer. Unlike the iron proteins, they do not require mild reduction for maximum activity. The linear relation between the intensity of absorption at 515 nm and phosphatase activity indicates that the metal is essential for catalysis. Neither manganese protein shows a room temperature ESR spectrum, but on add denaturation they show a spectrum characteristic of high-spin Mn". Little is known at present about the mechanism of these reactions. 

A manganese protein appears to be involved in the dioxygen-producing reaction in photosystem II. 

Iron Heme Proteins, Mono- Dioxygenases Iron-Sulfur Proteins Manganese Proteins with Mono- Dinuclear Sites. 

Manganese Proteins with Mono- Dinuclear Sites... 

MANGANESE PROTEINS WITH MONO- DINUCLEAR SITES... 

Many of these enzymes are known to be manganese dependent see Manganese Proteins with Mono- Dinuclear... 

Much effort has been put into the isolation, purification and reconstitution of both photosystems. Work on PSII has been concerned especially with the nature of the dioxygen-evolving site, which is thought to be a manganese protein. ESR studies on spinach chloroplasts have led to the postulate of the involvement in oxygen evolution of a pair (or possibly a tetramer) of antiferromagnetically... 

Mn and two Mn per molecule of protein have been suggested, but it is probable that only two are required at the reaction centre, and that there is a requirement for two additional divalent cations. These could well be involved in the control of protein conformations to ensure correct interactions between the manganese protein and the other components of the PSII centre. ... 

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