Cathode Information and Courses from MediaLab, Inc.
These are the MediaLab courses that cover Cathode and links to relevant pages within the course.
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| Hemoglobin Electrophoresis Theory Hemoglobin electrophoresis is the movement of hemoglobin proteins in an electric field at a fixed pH.Since different types of hemoglobin molecules are comprised of different combinations of globin chains (normal or abnormal), they will demonstrate different degrees of mobility. Typically, when a thalassemia or hemoglobinopathy is suspected, an alkaline electrophoresis is performed which may be confirmed with acid electrophoresis.For an alkaline hemoglobin electrophoresis, a hemolysate is applied to cellulose acetate which is electrophoresed in a buffer at pH 8.4-8.6. At this pH hemoglobin proteins move from cathode to anode. The proteins are visualized by the application of a dye which also makes them measurable by densitometry. | View Page |
| Migration of Hemoglobin in Alkaline Electrophoresis Of the hemoglobin types normally present in an adult, hemoglobin A migrates the fastest, followed by hemoglobin F. Hemoglobin A2 moves only slightly from the point of origin near the cathode.Abnormal hemoglobins show the following migration patterns:Hemoglobin C migrates with hemoglobin A2 near the cathode.Hemoglobin S lies between hemoglobin A2 and Hemoglobin F.Hemoglobin and Bart's hemoglobin are unstable and very fast moving placing them past hemoglobin A and near the anode with hemoglobin H being the fastest of the two.Relative migrations of hemoglobin variants on alkaline electrophoresis can be seen below. | View Page |
| Sample Alkaline Hemoglobin Electrophoresis Reading from cathode to anode (left to right):slight amount of hemoglobin A2, mostly hemoglobin Anear equal amounts of hemoglobin C and hemoglobin Ahemoglobin A and hemoglobin Hhemoglobin A2, hemoglobin S and hemoglobin Acontrol specimen hemoglobin F and hemoglobin Acontrol specimen hemoglobin C, hemoglobin S and hemoglobin A | View Page |
| In what order do normal and abnormal hemoglobins migrate in alkaline electrophoresis (from cathode to anode)? | View Page |
| Hemoglobin Electrophoresis Theory Hemoglobin electrophoresis is the movement of hemoglobin proteins in an electric field at a fixed pH.Because the various hemoglobins are comprised of different combinations of globin chains (normal or abnormal), they will demonstrate different degrees of mobility. Typically, when a thalassemia or hemoglobinopathy is suspected, an alkaline electrophoresis is performed which may be confirmed with acid electrophoresis.For an alkaline hemoglobin electrophoresis, a hemolysate is applied to cellulose acetate which is electrophoresed in a buffer at pH 8.4-8.6. At this pH hemoglobin proteins move from cathode to anode. The proteins are visualized by the application of a dye which also makes them measurable by densitometry. | View Page |
| Migration of Hemoglobin in Alkaline Electrophoresis Of the hemoglobins normally present in an adult, Hb A migrates the fastest, followed by Hb F. Hb A2 moves only slightly from the point of origin near the cathode.Abnormal hemoglobins show the following migration patterns:Hb C migrates with Hb A2 near the cathode.Hb S lies between Hb A2 and Hb F.Hb H (4 beta chains) and Bart's hemoglobin (4 gamma chains) are unstable and very fast moving, with Hb H being the faster of the two. They are located nearer the anode past Hb A .Relative migrations of hemoglobin variants on alkaline electrophoresis can be seen below. | View Page |
| Principle of Electrophoresis Charged particles under the influence of a liquid media placed in an electric field will migrate to the electrode of the opposite charge. Positive ions (cations) will migrate to the cathode, the negative electrode. Negative ions (anions) will migrate to the anode, the positive electrode.To get started, we will review terminology related to the charge characteristics of molecules. | View Page |
| The pI of a protein is 9.2. This protein is placed in an electrical field where a buffer sets the pH at 10.0. Select the correct statement regarding the electrophoretic migration of this protein. | View Page |
| Capillary Electrophoresis (CE) Capillary electrophoresis (CE) combines electrophoresis and high performance liquid chromatography. CE takes place in a very thin, fused silica capillary tube with polyacrylamide or agarose gel. Polyacrylamide is the most common gel used. The ends of the capillary tube are placed in two buffer reservoirs with the anode in one, and the cathode in the other. A high voltage power supply and cooling system are included.One major difference in CE is the detection of separated solutes as migration and separation occur, instead of detection after separation. An optical detector attached to the capillary detects solutes after separation but while still in the capillary; the detector is linked to data collection and storage. | View Page |
| Electroendosmosis With a pH 8.0-9.0 used for protein electrophoresis, proteins take on a negative charge, that is a negative ion cloud forms. As the negative ion cloud migrates to the anode, the proteins are pulled to the anode. Several gels used routinely for protein electrophoresis attract positive ions from the buffer and form a positive ion cloud. This ion cloud moves in the opposite direction to the cathode. This phenomenon is called electroendosmosis or endosmosis.The tension created by these oppositely moving ion clouds can affect the movement of sample macromolecules. The migration of some proteins can be slowed, some proteins can become immobile, and other proteins are pushed toward the cathode. Many protein electrophoresis methods take advantage of this tension and use it to achieve better separation of protein bands. The gamma globulin band in serum, urine, and other body fluids will separate more sharply by being pushed to the cathode and will appear behind the point of sample application. | View Page |
| Hemoglobin Electrophoresis Theory Hemoglobin electrophoresis is the movement of hemoglobin proteins in an electric field at a fixed pH.Because the various hemoglobins are comprised of different combinations of globin chains (normal or abnormal), they will demonstrate different degrees of mobility. Typically, when a thalassemia or hemoglobinopathy is suspected, an alkaline electrophoresis is performed which may be confirmed with acid electrophoresis.For an alkaline hemoglobin electrophoresis, a hemolysate is applied to cellulose acetate which is electrophoresed in a buffer at pH 8.4-8.6. At this pH hemoglobin proteins move from cathode to anode. The proteins are visualized by the application of a dye which also makes them measurable by densitometry. | View Page |
| Migration of Hemoglobin in Alkaline Electrophoresis Of the hemoglobins normally present in an adult, Hb A migrates the fastest, followed by Hb F. Hb A2 moves only slightly from the point of origin near the cathode.Abnormal hemoglobins show the following migration patterns:Hb C migrates with Hb A2 near the cathode.Hb E and Hb O also migrate with A2 and CHb S lies between Hb A2 and Hb F.Hb D and HbG migrate with S making accurate diagnosis difficult.Hb H and Bart's hemoglobin are unstable and very fast moving, with Hb H being the faster of the two. They are located nearer the anode past Hb A .Relative migrations of hemoglobin variants on alkaline electrophoresis are illustrated below. The application point is indicated by the arrow. | View Page |
| Migration of Hemoglobin in Acid Electrophoresis Acid electrophoresis (pH 6.0) is used to confirm or rule out the presence of abnormal hemoglobins that migrate with hemoglobin S in alkaline electrophoresis (pH 8.6), such as hemoglobins D. Hb A and F migrate from the center-point of application toward the cathode, with Hb F migrating the furthest.Relative migrations of hemoglobin variants on acid electrophoresis can be seen below. The application point is indicated by the arrow. As illustrated, hemoglobin D is now separated out from hemoglobin S. However, because it migrates with HbA in acid electrophoresis, further testing would be needed to identify HbD. | View Page |
