Which isoenzyme of ALP migrates the farthest toward the anode during electrophoresis at pH of 8.6?

The correct answer is that liver alkaline phosphatase (ALP) migrates the farthest toward the anode during electrophoresis at a pH of 8.6. This behavior is due to the differing isoelectric points (pI) of the various isoenzymes of ALP. The liver isoenzyme has a relatively lower pI compared to the other isoenzymes, meaning it has a higher net negative charge at this pH level.

As the electric field is applied during electrophoresis, proteins move toward the electrode of opposite charge. Since liver ALP carries a more negative charge at pH 8.6, it migrates faster and farther toward the anode than other isoenzymes such as bone, placental, or intestinal ALP, which have higher isoelectric points and thus carry less negative charge under the same conditions. This characteristic makes liver ALP a distinct marker in clinical laboratory testing, especially when assessing liver function and diagnosing various liver diseases.

Understanding the migration patterns of ALP isoenzymes is essential for interpreting electrophoretic results in a clinical setting, allowing for differentiation of conditions based on enzyme source.