Why the LDH isoenzymes can be separated by electrophoresis?

Answer 1

In the name of ALLAh , In order to answer this qustation Why the LDH isoenzymes can be separated by electrophoresis? .... we are going to answer this questions……….. 1) WHAT is ELECTROPHORESIS ? 2) BIOCHEMICAL COMPOSATION of LDH ? First .. I will introduce information about ELECTROPHORESIS :- What is Electrophoresis ? Electophoresis is aprocess of separating substance according to their electric charge which they carrying by introducing this substances in electrical media whish carrying out -ve and +ve poles . Electrophoresis is an analytical method frequently used in molecular Biology and medicine. It is applied for the separation and characterization of proteins, nucleic acids and subcellular-sized particles like viruses and small organelles. Its principle is that the charged particles of a sample migrate in an applied electrical field. If conducted in solution, samples are separated according to their surface net charge density. The most frequent applications, however, use gels (polyacrylamide, agarose) as a support medium. The presence of such a matrix adds a sieving effect so that particles can be characterized by both charge and size. Protein electrophoresis is often performed in the presence of a charged detergent like sodium dodecyl sulfate (SDS) which usually equalizes the surface charge and, therefore, allows for the determination of protein sizes on a single gel. Additives are not necessary for nucleic acids which have a similar surface charge irrespective of their size BIOCHEMISTERY of LDH :- Lactate dehydrogenase (LDH) catalyzes the reaction below. This reaction provides an important source of NAD+ for cells undergoing anaerobic glycolysis. Pyruvate + NADH + H+ <=> Lactate + NAD+ LDH is a tetrameric protein consisting of two types of subunits, called M and H, which have small differences in amino acid sequence. Different molecular forms of an enzyme are called isoenzymes or isozymes. M subunits predominate in skeletal muscle and liver, and H subunits predominate in heart. M and H subunits combine randomly with each other, so that the five major isoenzymes have the compositions M4, M3H, M2H2, MH3, and H4. Because of random subunit reassortment, the isoenzymic composition of a tissue is determined primarily by the activities of the genes specifying the two subunits. This propartey can indicate why LDH has electrophorises activity. ABD ELRHMAN OSAMA , abdelrhmanosama@Yahoo.com , 4th year faculty of medicine , Al-azher univ., Egypt .