Peroxisomes and its Functions

 Peroxisomes

Peroxisomes are otherwise known as microbodies. They are single - membrane vesicles of about 0.5 mm in diameter. They contain catalase, D-amino acid oxidase, urate oxidase and other oxidative enzymes.

Functions

Microbodies participate in the oxidation of certain nutrients. Hydrogen peroxide, the toxic reduction product of oxygen is decomposed to form water in these organelles.

Comments

Post a Comment

Popular posts from this blog

Cholesterol Biosynthesis

Image
  Cholesterol Biosynthesis Cholesterol is an animal sterol which occurs either free or as fatty esters. As it was first isolated from human gallstones deposited in the bile duct, it is named as cholesterol (Greek word chole means – bile, sterol). Cholesterol is composed of 1,2-cyclopentanoperhydrophenanthrene ring system. Although cholesterol is an essential compound for life for the synthesis of hormones, bile acids and vitamin D, it is not necessary to supply it in the diet because it can be synthesised in the cell from acetyl CoA Carbohydrates, amino acids, fatty acids and glycerol which gets converted to Acetyl CoA can also serve as a source for cholesterol synthesis. The liver plays a decisive role in the cholesterol metabolism which accounts for 90% of the overall endogenic cholesterol and its esters. A man weighing 70 kg contains about 140 grams of cholesterol. The cholesterol concentration of blood in human is between 150 to 250 mg per 100 ml, being distributed equally between
Read more

Purine bases: Structure and Properties

Image
  Purine bases Structure of purine bases Purine bases are derived from the parent compound purine. Purine contains the heterocyclic ring system. Fusion of the pyrimidine ring with imidazole yields the purine ring (Fig. 7.2). The purine bases present in nucleic acids are adenine and guanine. Other purine bases are hypoxanthine and xanthine. They are intermediates in the formation of adenine and guanine nucleotides. Properties of purine bases ·             Purine bases are sparingly soluble in water. ·             They absorb light in UV region at 260 nm. This property is used for the detection of and the quantification of purine nucleotides. ·             They are capable of forming hydrogen bonds. ·             They exhibit keto-enol tautomerism at body pH.
Read more

Digestion of Nucleic acids

  Digestion of Nucleic acids   1.  Digestion in mouth and stomach There are no enzymes to digest nucleic acids in the mouth. The highly acidic medium in the stomach destabilizes the nucleoprotein structure and the proteolytic enzymes split them to nucleic acids and proteins.   2. Digestion in duodenum   Pancreatic juice contains two enzymes ribonuclease and deoxylribonuclease that can hydrolyze the nucleic acids to mononucleotides.   Depending upon the site of action, nucleases canbe either endonuclease that attacks the interior linkages and exonuclease that attacks the terminal linkages.   The intestinal juice (succus entericus) contains the following two enzymes that digest nucleic acids.   ·                Nucleotidases that hydrolyze nucleotides to nuclosides and phosphoric acid. ·                Nucleosidases that hydrolyzes the nucleosides to their respective sugars and bases.   3.  Gastro Intestinal Hormones There are three major gastro intestinal hormones secreted by the gut. T
Read more