protoporphyrin IX n.
A porphyrin derivative that combines with ferrous iron to form the heme of hemoglobin and with ferric or ferrous iron to form the prosthetic groups of substances such as myoglobin, catalase, and the cytochromes.
|a chattering or flighty, light-headed person.|
|an arrangement of five objects, as trees, in a square or rectangle, one at each corner and one in the middle.|
Dictionary.com presents 366 FAQs, incorporating some of the frequently asked questions from the past with newer queries.