Differences in the reduction kinetics of incorporated spin labels in undifferentiated and differentiated mouse neuroblastoma cells.

Abstract

Significant differences in the rate of reduction of two spin labels, 5-doxylstearic acid and TEMPOL, in the undifferentiated and differentiated NB-15 mouse neuroblastoma cells were demonstrated by using electron paramagnetic resonance (EPR) spectroscopy. The half-time (T1/2) values for decay of the EPR signal of 5-doxylstearic acid in the undifferentiated and differentiated neuroblastoma cells were 70 min and 290 min, respectively. The T1/2 values of TEMPOL in the undifferentiated and differentiated cells were 18 min and 34 min, respectively. The cellular reductant was characterized as non-protein-bound sulfhydryl groups. A corresponding difference in the cellular non-protein-bound sulfhydryl content, 19.30 nmol/mg protein for the undifferentiated cells and 6.78 nmol/mg protein for the differentiated cells, was observed. Comparison of the reduction rates of TEMPOL, 5-doxylstearic acid and 16-doxylstearic acid in the undifferentiated NB-15 cells suggested that the permeation of non-protein-bound sulfhydryl compounds from the cytosol to membrane may be responsible for the reduction of the lipid-soluble stearic acid spin labels.

• Authors: K Y Chen, M G McLaughlin
• Journal: Biochimica et biophysica acta (Biochim Biophys Acta) Vol. 845 Issue 2 Pg. 189-95 (May 30 1985) ISSN: 0006-3002 [Print] Netherlands
• PMID: 2986718 (Publication Type: Comparative Study, Journal Article, Research Support, Non-U.S. Gov't, Research Support, U.S. Gov't, P.H.S.)

Chemical References

• Cyclic N-Oxides
• Spin Labels
• Sulfhydryl Compounds
• 5-doxylstearic acid
• 16-nitroxystearic acid
• tempol

Topics

• Animals
• Cell Differentiation
• Cell Line
• Cell Membrane (metabolism)
• Cyclic N-Oxides (metabolism)
• Electron Spin Resonance Spectroscopy
• Half-Life
• Kinetics
• Mice
• Neuroblastoma (metabolism, pathology)
• Oxidation-Reduction
• Spin Labels
• Sulfhydryl Compounds (metabolism)