manganesedependent

Manganesedependent refers to enzymes and biochemical processes that require manganese ions (Mn2+) as essential cofactors for catalytic activity. In these enzymes, Mn2+ is bound at the active site and participates directly in chemical transformations, often by activating substrates, stabilizing intermediates, or cycling between oxidation states during catalysis. Depending on the organism and context, Mn2+ may be preferred over other divalent metals for particular reactions.

Notable examples of manganese-dependent enzymes include manganese superoxide dismutase (MnSOD), which protects cells from oxidative damage by catalyzing the dismutation of superoxide radicals into oxygen and hydrogen peroxide; MnSOD commonly resides in mitochondria and in bacteria. Arginase is another Mn-dependent enzyme that hydrolyzes arginine to ornithine and urea, playing a key role in the urea cycle and polyamine synthesis. In some bacteria, certain ribonucleotide reductases use manganese in their metal centers to convert ribonucleotides to deoxyribonucleotides, a vital step in DNA synthesis.

Physiologically, organisms regulate manganese uptake, storage, and efflux to maintain adequate Mn-dependent enzyme activity while avoiding toxicity. Mn availability in the environment and cellular metal homeostasis influence the expression and activity of manganese-dependent enzymes. Deficiencies or imbalances can impair processes such as oxidative stress defense and nitrogen metabolism, underscoring the importance of Mn2+ in diverse biological systems.