Manganese binding with proteins

Copper is an essential element. It is of a great importance in the metabolic processes of plants, its content in plant tissues being very low, much lower than those of zinc and manganese. Copper ions form complexes with proteins and with the other biopolymers in plant tissues. These complexes are more stable than those of the other metals. Binding to proteins enhances the catalytic activity of copper. Copper participates in many oxidation-reduction enzymatic systems, and it is thus of importance particularly in respiration and photosynthesis processes. In plants it is also essential in the nitrogen metabolism. Its concentration in plants ranges... 

Left side of Fig. 4 shows a ribbon model of the catalytic (C-) subunit of the mammalian cAMP-dependent protein kinase. This was the first protein kinase whose structure was determined [35]. Figure 4 includes also a ribbon model of the peptide substrate, and ATP (stick representation) with two manganese ions (CPK representation). All kinetic evidence is consistent with a preferred ordered mechanism of catalysis with ATP binding proceeding substrate binding. 

Ovotransferrin is also obtained from the white portion of a chicken egg and has been used as a chiral selector in liquid chromatography. This protein is also called conalbumin. It is a metal ion (iron, copper, manganese, and zinc) binding protein of molecular mass 70,000-78,000 and with an isoelectric point of 6.1-6.6. This protein is sensitive to acids and heat. 

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