hemerythrins

he·me·ryth·rins

(hē-mĕ-rith'rinz, hem-ĕ-),
Iron-containing, oxygen-binding proteins in certain invertebrates, with molecular weights approximately that of hemoglobin but differing from hemoglobin in that the molecules do not contain porphyrin groups. Oxygenated hemerythrins is oxyhemerythrin.
[G. haima, blood, + G. erythros, red, + -in]