[Multiple forms of certain enzymes result post-translationally by a modification of sugar or protein moieties]

Multiple forms of a certain enzyme may result from at least two mechanisms: first, allozymes are coded by distinct genes which exist in separate locus on the chromosome or processed by shuffling of distinct exons on the same genome, and second is this subject, so-called isozymes biosynthesized from single gene subsequently become distinguishable from each other as a result of post-translational modification by protease cleavage (CK), deamidation (AMY) and sugar (ALP, GGT, AMY) or GPI-anchor (ALP) moieties attaching to the enzyme molecules. Therefore, it is interesting to speculate whether alternative forms of the above-mentioned enzymes are true isozymes synthesized from a mRNA from single and/or different cells. In this section, the current topics of these isozymes are commented or discussed.