Microsome
As microsomes small pieces of membrane of about 100 nm diameter are referred to from fragments of the smooth ERs were recovered. They should not be confused with vesicles that are pinched off by membranes in vivo . Microsomes are used to study ER-bound enzymes . The preparation is carried out by cell disruption , differential centrifugation and homogenization. However, they can also arise artificially in preparations with other objectives.
Most often, microsomes are prepared in order to obtain functional cytochrome P450 enzymes (CYPs). Their activity is often only guaranteed in the presence of a multipart protein system, such as that found in the membrane of the smooth ER. When CYPs are obtained in microsomes, the protein membrane system is preserved, which enables the metabolic characterization or biotechnological use of CYPs. Microsomes can be obtained from various animal and human organs, often from the liver , lungs and kidneys . If the microsomes are to contain only one specific CYP or if larger amounts of CYP are required, the corresponding microsomes are obtained by heterologous expression from Escherichia coli or Sf-9 cells , for example .
Sometimes microsomes are also prepared to study other enzymes, such as phosphatidyl synthase, which in humans is used in catalysis to convert phosphatidylethanolamine into phosphatidylserine in glycerophospholipid biosynthesis.
literature
- Joachim Rassow, Katrin Hauser, Roland Netzker, Rainer Deutzmann: Biochemistry . 1st edition. Thieme-Verlag, Stuttgart 2006, ISBN 3-13-125351-7 .
Individual evidence
- ^ Donald Voet, Judith G. Voet: Biochemistry , 3rd. Edition, Wiley, 2004, ISBN 0-471-19350-X , p. 1309.
- ↑ Heterologous expression of human cytochromes P450 2D6 and CYP3A4 in Escherichia coli and their functional characterization. Protein J. 2011 Dec; 30 (8): 581-91
- ↑ Co-expression of human cytochrome P4501A1 (CYP1A1) variants and human NADPH-cytochrome P450 reductase in the baculovirus / insect cell system. Xenobiotica. 2001 Jun; 31 (6): 345-56.