And one way by which our body is able to actually regulate and fine tune these specific biochemical processes in the different types of cells in our body is by using molecules known as isozymes or Isa enzymes. And we actually discussed many examples of isozymes previously. For instance, when we discussed the regulatory pathway of glycolysis in skeletal muscle cells and liver cells, we said that pyruvate kinase, the enzyme that catalyzes the final step in glycolysis that we find in skeleton muscle cells and in liver cells, actually come in different forms. In muscle cells, we have predominantly the misosign, but in liver cells we have predominantly that l isosine of pyruvate kinase. And although they carry out the same type of catalytic and regulatory process, they do have slightly different properties. And that's because they have slightly different amino acid sequences and slightly different structures.