So each one of these red chains is basically that Mi design chain. On the other hand, if we study the cardiac muscle cells, we're going to see the coronary structure of the LDH basically consists of four individual H I design chains and these are shown in purple. So this lactate dehydrogenase, which is basically denoted with H four, where H means we have the H ISome and four means we have four of these individual A chains. So we have this lactate dehydrogenase is made up of four A chains and it's found in cardiac muscle cells, while the M four, which basically consists of these four individual M isotime chains, makes up the LDH that predominates in skeletal muscle cells. So we see that it's this molecule, the M four, that operates at a maximum efficiency inside skeleton muscle cells where we typically have a lower oxygen concentration. But it's this purple H four LDH molecule that predominates in cardiac muscle cell which operates at a maximum efficiency when there's a high concentration of oxygen, as we typically find in the heart, in the cardiac muscle cell.