Differentiation of human alkaline phosphatases by lectin binding affinity

Area of Science:

• Biochemistry
• Molecular Biology

Background:

• Human alkaline phosphatases exist in multiple isoenzyme forms.
• Understanding these isoenzymes is crucial for diagnostics and research.
• Previous studies utilized structural, catalytic, or immunological properties for classification.

Purpose of the Study:

• To investigate the utility of lectin binding affinity for separating human alkaline phosphatase isoenzymes.
• To characterize the isoenzyme classes of human alkaline phosphatases based on carbohydrate structures.
• To identify potential microheterogeneity within alkaline phosphatase isoenzymes.

Main Methods:

• Purification of human alkaline phosphatases.
• Separation of isoenzymes using affinity chromatography with Wheat germ lectin-Sepharose, Concanavalin A-Sepharose, and Lentil lectin-Sepharose.
• Analysis of lectin binding properties.

Main Results:

• Three distinct human alkaline phosphatase isoenzymes were successfully separated: placental, intestinal, and liver-bone-kidney types.
• The carbohydrate chains of these purified alkaline phosphatases align with established isoenzyme classes.
• The liver-bone-kidney-type isoenzyme exhibited previously undescribed microheterogeneity when analyzed with Concanavalin A and Lentil lectin.

Conclusions:

• Lectin binding affinity is a valuable and effective method for purifying and separating human alkaline phosphatase isoenzymes.
• This approach provides insights into the carbohydrate structures of alkaline phosphatase isoenzymes.
• The observed microheterogeneity in the liver-bone-kidney isoenzyme warrants further investigation.