(1) As a reductant , it is very important in maintaining the stability of erythrocyte membranes and the structure of hemoglobin.(2) Other species can serve as sources of hydrogen or electrons and likewise participate in redox reactions as reductants .(3) The non-microbial sinks include oxidation of inorganic reductants in the soil, such as Fe, which may be both mobile and immobile.(4) Carbohydrates not only provide the acceptor of sulphide for cysteine biosynthesis, they are the source of reductants for sulphate reduction in non-photosynthetic tissues.(5) Some substances are capable of acting either as reductants or as oxidants, e.g., hydrogen peroxide and nitrous acid.
