Biochemical reactions - nitrate assimilation, Biology

Biochemical Reactions - Nitrate Assimilation

Nitrate is the most readily available and preferred source of nitrogen for growth. Assimilatory reduction of NO-3 to NH3 is known to occur in two steps as shown below:

1939_Biochemical Reactions - Nitrate Assimilation.png

The first step is catalysed by nitrate reductase (NR) which reduces NO-3 to NO-2 at the expense of two electrons. The second step is catalysed by nitrite reductase which - converts NO-2 into NH3 at the expense of six electrons. Nitrate reductase is Mo-enzyme like dinitrogenase and nitrite reductase is Fe-protein. The physiological source of reductant for the two reductive processes could be reduced ferredoxin - Fd(red) or reduced pyridine nucleotides (NADH or NADPH) depending upon the system. It is important to point out here that NO-3 is known to undergo dissimilation in which it is reduced to N2 gas. Such a process of nitrate metabolism is called nitrate respiration or denitrification and occurs exclusively in certain bacterial forms under anaerobic condition. The enzymes of denitrification of nitrate are called dissimilatory nitrate reductases.

Posted Date: 1/17/2013 5:22:30 AM | Location : United States







Related Discussions:- Biochemical reactions - nitrate assimilation, Assignment Help, Ask Question on Biochemical reactions - nitrate assimilation, Get Answer, Expert's Help, Biochemical reactions - nitrate assimilation Discussions

Write discussion on Biochemical reactions - nitrate assimilation
Your posts are moderated
Related Questions
Dominance In each community, a few over topping species are present in greater bulk. By their greater number or biomass (living weight) the dominant species modify the habitat

What are compound eyes? Arthropods have compound eyes made of many visual units called ommatidia. Every ommatidium transmits visual information by the optic nerve to the brain,

What is meant by cellular secretion? Cell secretion is the elimination to the exterior of substances formed by the cell (for instance, hormones, mucus, sweat, etc.)

Precautions to prevent from HIV  To avoid HIV infection one should practice safe sex (use of condoms). Besides a few simple precautions are given for protection against HIV inf

Explain the Disadvantages of Colonies Obtained At Different Dilution 1. Heat sensitive microorganisms may be damaged by melted agar, giving low viable count as compared to spre

State the basic properties of Cell The differences of cell types notwithstanding, the similarities among them are more profound. Actually, all cells possess the same basic prop

Define Briefly about the Copper? As early as the times of Hippocrates, copper compounds were used to treat various diseases. However, in the 20" century, it was noticed that an


Vitellogenesis Vitellogenesis is the stage where much of the oocyte growth occurs. The completion of second maturation division (meiosis), which may occur after ovulation, res

Effect of pH or Nutrient Availability One of the greatest influence of pH on plant growth is through its effect on the nutrient availability. When base saturation is less than