Category Nuances for heme:

• physiological,
• colored,
• biological,
• iron,
• prosthetic,
• molecular,
• important,
• inhibitory,
• cellular,
• aromatic,
• natural,
• organic,
• essential,

Simple Categories for heme:

• substrate,
• component,
• entity,
• substance,
• group,
• porphyrin,
• pigment,
• material,