抄録
1. Studies on the developmental formation of heme α-methenyl oxygenase in guinea pig tissues were performed using pyridine-hemichromogen as a substrate.
2. The activity was found to be negligible in homogenates of various tissues in early fetal stages.
3. The deficit of the activity in the fetal liver seemed to be due to the absence of active enzyme protein.
4. The activity appeared in the fetal liver near term and increased to adult levels by 3 to 5 days after birth.
