<prompt> Heme is which porphyrin:Type IType IIType IIIType IV  <response>: The side chain groups in porphyrins may be arranged in four different structural configurations I to IV. Only type I and type III series are found in nature and the porphyrins of type III series are not only more abundant but are also physiologically impoant in humans. Haem is a type III porphyrin. 