Microsome

Microsomes are small (about 100 nm in diameter) membrane - limited vesicles within cells. Are fragments of the smooth and rough endoplasmic reticulum (ER ), which are also formed in the homogenization of tissue, for example. Microsomes can be easily isolated by centrifugation. They are used to study the ER- bound enzymes.

In microsomal cytochrome P450 enzymes are included. These play a major role in the oxidative metabolism. Therefore, microsomes are often used in the in vitro metabolism to identify the individual isoenzymes. This microsomes from human liver are mainly used, but some and from the lung or the kidney. Furthermore, microsomes often recovered from animal organs in order to carry out tests described above.

Also microsomes of human cells containing the enzyme phosphatidyl synthase, which serves to catalyze the conversion of phosphatidylethanolamine to phosphatidylserine in glycerophospholipid biosynthesis.