Mikrosomes

Mikrosomes are small, vesicle-like structures that are formed from the fragmented endoplasmic reticulum (ER) when cells are broken apart or homogenized. They are typically derived from the rough or smooth ER and consist of a lipid bilayer membrane enclosing enzymes and other ER components. Mikrosomes are commonly used in biological and medical research to study cellular metabolic processes, especially those involving enzyme activity.

Historically, mikrosomes gained prominence in studies of drug metabolism, particularly in the context of the liver. Liver microsomes, a type of mikrosome preparation, contain enzymes such as cytochrome P450 monooxygenases that play a crucial role in phase I drug metabolism, including oxidation, reduction, and hydrolysis reactions. These microsomal preparations are used to simulate and analyze how drugs are processed in the human body.

Mikrosomes are produced through differential centrifugation, where homogenized tissue or cell samples undergo centrifugation at specific speeds to isolate ER fragments. The resulting mikrosomal fractions are characterized by their density and enzyme activity levels.

Aside from pharmacological research, mikrosomes are utilized in studying lipid synthesis, detoxification pathways, and cellular responses to toxins. Their ability to maintain enzymatic activity outside of living cells makes them valuable tools for biochemical assays.

While the term "mikrosome" is less frequently used today, replaced often by "microsome," it remains a fundamental concept in cell and molecular biology for understanding intracellular enzyme functions and drug metabolism mechanisms.