Slow-migrating pancreatic-type (slow-P) amylase variants detected electrophoretically.

Four types of the hereditary variant human amylase (AMY) of pancreatic (P) origin have been reported as slow-P, dominant-P2, dominant-P2S, and dominant-P2MS by AMY isoenzyme on cellulose acetate membrane electrophoresis. Since 1990, we examined 84, 084 samples for serum and urine AMY isoenzymes, and found AMY bands which showed slower migration than P1-AMY, the main band of P-AMY, in 24 serum samples. These bands did not react with the anti-human salivary (S)-type AMY activity inhibitory monoclonal antibody, suggesting that these bands seemed to be derived from P-type AMY. When slow-P AMY bands were classified by the relative distance ratio of slow-P AMY and P1-AMY bands to P1-AMY and S1-AMY bands, it was found that there were 3 variants. The slow-P AMY variants were for convenience' sake named slow-P1 AMY (mean±1SD of the relative distance ratio: 0.518±0.043), slow-P2 AMY (0.635±0.024), and slow-P3 AMY (0.985±0.022) progressively from the anode side. The frequency of 3 slow-P AMY variants in Japanese is estimated at 0.007% (6/84, 084) for slow-P1 AMY, 0.019% (16/84, 084) for slow-P2 AMY, and 0.002% (2/84, 084) for slow-P3 AMY. At present, however, there is no evidence that these bands are genetic variants because pancreatic juice from patients and their family lines have not yet been examined.