What is non-microsomal reaction?

The flavoprotein oxidases, esterases, amidases and conjugases are nonmicrosomal. Reactions catalysed are: NON-MICROSOMAL ENZYMES. These are present in the cytoplasm and mitochondria of hepatic cells as well as in other tissues including plasma.

What are non-microsomal enzymes?

Non-microsomal enzymes: Enzymes occurring in organelles/sites other than endoplasmic reticulum (microsomes) are called non-microsomal enzymes. These are usually present in the cytoplasm, mitochondria, etc. and occur mainly in the liver, Gl tract, plasma and other tissues.

What are non synthetic reactions?

Phase I reactions (also termed nonsynthetic reactions) may occur by oxidation, reduction, hydrolysis, cyclization, decyclization, and addition of oxygen or removal of hydrogen, carried out by mixed function oxidases, often in the liver.

What are the consequences of biotransformation?

In some cases, biotransformation results in the formation of reactive oxygen species which can cause cellular toxicity, including DNA damage through oxidative stress and lipid peroxidation.

What is microsomal metabolism?

Drugs are metabolized in the liver using several enzyme-catalyzed processes. These enzymes are collectively referred to as the hepatic microsomal enzyme system, and they are usually present in the endoplasmic reticulum of hepatocytes.

What is microsomal enzyme system?

A collection of enzymes in the smooth endoplasmic reticulum of liver cells that modify molecules to make them more POLAR and less lipid-soluble.

What is biotransformation metabolism?

Biotransformation is a metabolic process that takes place mainly in the liver and helps to facilitate the excretion of both exogenous and endogenous substances. A series of reactions alter the chemical structures of these substances.

What is drug biotransformation?

Biotransformation is the metabolic process by which the liver alters or modifies substances entering the body, such as drugs. The process takes place through an interaction of substrates with the cytochrome P450 family of enzymes.

What is the role of amidase in Phase I metabolism of xenobiotics?

Hydrolase and amidase activities (Hodgson, 2008) are known to be important in phase I metabolism of xenobiotics, including pesticides. For example, dimethoate is detoxified by amidase activity and the selective toxicity of malathion is due, in large part, to the presence in mammals of carboxylesterases not widely distributed in insects.

What are the steps in Phase 1 of drug metabolism?

•Phase I Reactions –Oxidation –Reduction –Hydrolytic cleavage –Alkylation (Methylation) –Dealkylation –Ring cyclization –N-carboxylation –Dimerization –Transamidation –Isomerization –Decarboxylation B I M M 1 1 8 Drug Metabolism – Oxidation Two types of oxidation reactions:

What are Phase I and Phase II reactions in drug metabolism?

– Often these metabolites are inactive – May be sufficiently polar to be excreted readily • Phase II Reactions – Conjugation with endogenous substrate to further increase aqueous solubility – Conjugation with glucoronide, sulfate, acetate, amino acid – Phase I usually precede phase II reactions Liver is principal site of drug metabolism:

What are the types of oxidation reactions in drug metabolism?

Drug Metabolism – Oxidation Two types of oxidation reactions: –Oxygen is incorporated into the drug molecule (e.g. hydroxylation) –Oxidation causes the loss of part of the drug molecule (e.g. oxidative deimination, dealkylation) Microsomal Mixed Function Oxidases (MFOs) • “Microsomes” form in vitro after cell homogenization and fractionation of ER