Details

Autor(en) / Beteiligte

• Yun, Chul-Ho
• Ahn, Taeho
• Guengerich, F.Peter

Titel

Conformational Change and Activation of Cytochrome P450 2B1 Induced by Salt and Phospholipid

Ist Teil von

• Archives of biochemistry and biophysics, 1998-08, Vol.356 (2), p.229-238

Ort / Verlag

United States: Elsevier Inc

Erscheinungsjahr

1998

Quelle

Access via ScienceDirect (Elsevier)

Beschreibungen/Notizen

• A stimulatory effect of increased salt concentration on the enzymatic activity of rat liver microsomes and a reconstituted system containing cytochrome P450 (P450) 2B1 and NADPH-P450 reductase was seen. Structural change of P450 2B1 accompanying the salt-induced increase in its enzyme activity was investigated by circular dichroism, fluorescence spectroscopy, and absorption spectroscopy. It was found that the salt increased α-helix content of P450 2B1 in the presence as well as in the absence of a phospholipid. Intrinsic fluorescence emissions also increased with increasing salt concentration. The low-spin iron configuration of P450 2B1 shifted toward the high-spin configuration in response to the increased salt concentration. It was found that the activity increase of P450 coincides with the raised α-helix content. The presence of phospholipid magnified this effect. It is proposed that the interaction with salts and phospholipid molecules surrounding P450 2B1 in the endoplasmic reticulum is important for a functional conformation of P450 2B1 in a monooxygenase system including NADPH-P450 reductase.