Abstract
The parasitic nematode Ascaris infests a billion people worldwide. Much of its proliferative success is due to prodigious egg production, up to 106 sterol-replete eggs per day. Sterol synthesis requires molecular oxygen for squalene epoxidation, yet oxygen is scarce in the intestinal folds the worms inhabit. Ascaris has an oxygen-avid hemoglobin in the perienteric fluid that bathes its reproductive organs. Purified hemoglobin contained tightly bound squalene and functioned as an NADPH-dependent, ferrihemoprotein reductase. All components of the squalene epoxidation reaction - squalene, oxygen, NADPH, and NADPH-dependent reductase - are assembled on the hemoglobin. This molecule may thus function in sterol biosynthesis.
| Original language | English |
|---|---|
| Pages (from-to) | 1930-1932 |
| Number of pages | 3 |
| Journal | Science |
| Volume | 258 |
| Issue number | 5090 |
| State | Published - Dec 18 1992 |