The pair in which both the species have iron is:

Options

A. nitrogenase, cytochromes
B. carboxypeptidase, haemoglobin
C. haemocyanin, nitrogenase
D. haemoglobin, cytochromes

Answer

D

Explanation

Cytochromes are conjugated proteins consisting of an apoprotein and a prosthetic group `(` haeme`)`. The haeme consists of a porphyrin with a central iron atom.
The name haemoglobin is the concatenation of haeme and globin, relecting the fact that each subunit of haemoglobin is a globular protein with an embedded heme `(` or haem`)` group , each heme group contains an iron atom, and this is responsible for the binding of oxygen. The most common types of haemoglobin contains four such subunits , each with one heme group.