次生性同工酶(secondary isozyme)是指酶蛋白在内质网上合成时或合成后经不同的修饰反应而产生的同一种酶的不同分子形式。这些修饰反应包括磷酸化、乙酰化、酰胺水解、肽链切断、二硫键生成及糖链的添加等。因一般发生在酶蛋白翻译之后,故又称翻译后同工酶。国际生化命名委员会认为这种同工酶的生成并非发生在基因水平,应称为Synzyme比较恰当。在这些修饰反应中,糖链的添加最引人注目,这是不同组织中糖蛋白性同工酶产生的主要原因。如众所周知的碱性磷酸酶 Secondary isozyme refers to different molecular forms of the same enzyme produced by different modification reaction of enzyme protein during the synthesis of endoplasmic reticulum or after synthesis. These modification reactions include phosphorylation, acetylation, amide hydrolysis, peptide chain cleavage, disulfide bond formation and sugar chain addition. Because generally occurs after the enzyme protein translation, it is also known as post-translational isozymes. The International Committee for Biochemical Names believes that the production of this isozyme does not occur at the gene level and should be called Synzyme more appropriate. In these modification reactions, the most noticeable addition of sugar chains is the main reason for the glycoprotein isozymes in different tissues. Such as the well-known alkaline phosphatase