Question

Which of the following enzymes requires molybdenum as the co-factor?
A.Carboxylase
B.Hexokinase
C.Flavin oxidase
D.Nitrate reductase

Answer 1

Molybdenum is present in all organisms in traces which is important for both animal and plant diet. It is a cofactor for various enzymes, it catalyzes chemical transformations in carbon, nitrogen, and sulfur cycle in the ecosystem. It helps in proton, electron, and oxygen transfer in the human body. A cofactor is a non-protein chemical or metallic ion catalyst required by enzymes to accelerate the biochemical transformations which do not bind to the enzymes and are called helper molecules.

Complete step by step answer: Option A- Carboxylase
The enzyme carboxylase is dependent on biotin as a cofactor that transfers carbon dioxide to the site of action in the form of carboxybiotin.
Option B- Hexokinase
This enzyme converts glucose into glucose-6-phosphate by adding a phosphate group by using energy in the form of ATP. Kinases are the enzymes that catalyze the transfer of phosphate group from ATP molecule to some other substance or molecule.
Option C- Flavin oxidase
Flavin is the cofactor of monoamine oxidase which takes part in redox reactions. Oxygen reacts with flavin and forms flavin hydroperoxide, which is used in hydroxylations.
Option D- Nitrate reductase
This enzyme catalyzes the reaction of nitrate assimilation in plants, algae, and fungi with the help of the molybdenum cofactor. Nitrate assimilation is a biological process of conversion of nitrogen to organic nitrogen.
Thus, the correct option is option D- Nitrate reductase.

Note: The main function of the element in the human body is the breaking down of amino acids. Deficiency of molybdenum in humans causes seizures, lens dislocation, intellectual disability, nausea, vomiting, tachycardia, coma, etc. Toxicity can cause high levels of molybdenum in blood, uric acid, etc.