Measurement of isoenzymes and isoforms

A number of analytical techniques have been used to measure isoenzymes or isoforms. They include electrophoresis (see Chapter 5), chromatography (see Chapter 6), chemical inactivation, and differences in catalytic properties, but the most common routine methods are now based on immunochemical methods. 

BAP measurement methods have used heat inactivation, chemical inhibition, electrophoresis, isoelectric focusing, lectin precipitation and chromatography, HPLC, and other approaches, singly and in combination. Conventional elec-trophoresis provides qualitative, not quantitative, detection because of the overlapping migration of isoforms and isoenzymes. Heat inactivation and chemical inhibition with urea, hphenylalanine, 1-homoarginine, or levamisole have been used with some success. Internal standards of ALP isoenzymes have been used to increase assay precision. 

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