PHB231 Lab (5) Hemoglobin Precipitation PDF

Faculty of Pharmacy Biochemistry Department Biochemistry 1 (PHB231) Prepared by: A.L Heba Elrefaie T.A Mariam Sabry  What are Heme proteins?  Hemeproteins are proteins that contain a heme prosthetic group.  They have several functions including:  Oxyge...

Faculty of Pharmacy Biochemistry Department Biochemistry 1 (PHB231) Prepared by: A.L Heba Elrefaie T.A Mariam Sabry  What are Heme proteins?  Hemeproteins are proteins that contain a heme prosthetic group.  They have several functions including:  Oxygen transport  Oxygen reduction  Electron transfer and other processes.  Hemoglobin and Myoglobin  They are the most abundant heme proteins in humans.  The main function of their heme group is the reversible binding of molecular oxygen.  Hemoglobin and Myoglobin (i) Function  Hemoglobin:  It is present in the RBCs.  Its main function is to transport O2 from lungs to tissues.  It can also transport CO2 from tissues to lungs.  Hemoglobin and Myoglobin (i) Function  Myoglobin :  It is present in the heart and skeletal muscles.  It carries and stores O2 in the muscle cells.  Hemoglobin and Myoglobin (ii) Structure  Hemoglobin:  It has a quaternary structure.  It is composed of 4 subunits (2α chains and 2β chains).  Each chain contains a heme group, hence Hb binds to 4 oxygen molecules  Hemoglobin and Myoglobin (ii) Structure  Myoglobin :  It has a tertiary structure.  It is composed of only one polypeptide chain (8 α helices designated A-H).  It has only one heme group so it binds to only one oxygen molecule.  Hemoglobin and Myoglobin (iii) Abnormalities  Hemoglobinuria:  It is the presence of hemoglobin in urine rendering the colour of urine dark red or brown.  Causes:  Hemoglobin and Myoglobin (iii) Abnormalities  Hemoglobinuria:  Hemoglobin exceeds the amount of Hb-haptoglobin complex in:  Hemolytic anemia.  Severe burns.  Blood transfusion reactions.  Strenuous exercise.  Infections  Hemoglobin and Myoglobin (iii) Abnormalities  Myoglobinuria:  It is the presence of myoglobin in urine rendering the colour of urine dark red or brown.  Causes:  Rhabdomyolysis  distal tubular toxicity  Hemoglobin and Myoglobin (iv) Chemical Test Ammonium Sulphate Precipitation Test  Principle:  This test is used to differentiate between hemoglobinuria and myoglobinuria.  It is based on the principle that hemoglobin requires 80% saturation of ammonium sulphate in urine to precipitate, whereas myoglobin requires 100% saturation to precipitate. Faculty of Pharmacy