Isoenzyme, true is

They are physically distinct forms of the same enzyme activity. Multiple molecular forms of an enzyme are described as iso-enzymes or isozymes. If 50 paise coins are examined carefully, there will be minor variations of ridges on the rims and number of dots below the year. In the market all these coins have the same face value; but to an experienced numismatist, these variations will explain from which mint it was produced. In the same way, different molecular forms of the same enzyme synthesized from various tissues are called isoenzymes. Hence study of iso-enzymes is very useful to understand diseases of different organs. If the subunits are, all the same, the protein is a homomultimer represented by a single gene. If the subunits are different, protein is said to be a heteromultimer, produced by different genes.Ref: DM Vasudevan, Page no: 59