Artefactual spherical particle, not present in the living cell, derived from pieces of the endoplasmic reticulum present in homogenates of tissues or cells: microsomes sediment from such homogenates when centrifuged at 10E6 g and higher: the microsomal fraction obtained in this way is often used as a source of mono-oxygenase enzymes.
Source:
PAC, 1993, 65, 2003. 'Glossary for chemists of terms used in toxicology (IUPAC Recommendations 1993)' on page 2070 (https://doi.org/10.1351/pac199365092003)