Purification and partial characterization of the phosphoglucomutase isozymes from human placenta

Area of Science:

• Biochemistry
• Enzymology
• Molecular Biology

Background:

• Phosphoglucomutase (PGM) isozymes are crucial enzymes in carbohydrate metabolism.
• Human placenta is a rich source of PGM isozymes with high specific activity.
• Previous purification methods have been employed using human erythrocytes.

Purpose of the Study:

• To develop a simple and efficient procedure for purifying phosphoglucomutase (PGM) isozymes from human placenta.
• To obtain homogeneous preparations of PGM1 and PGM2 isozymes for molecular-level studies.
• To compare the properties of PGM isozymes purified from placenta with those from erythrocytes.

Main Methods:

• Ammonium sulfate fractionation
• Ion-exchange chromatography
• Dye-ligand chromatography
• SDS-polyacrylamide gel electrophoresis (SDS-PAGE)

Main Results:

• Homogeneous preparations of PGM1 and PGM2 isozymes were obtained from human placenta.
• Purified PGM1 and PGM2 isozymes showed specific activities of 1134.6-1441.8 units/mg and 40.2-46.5 units/mg, respectively.
• SDS-PAGE confirmed the purity with single protein bands at Mr 58,500 (PGM1) and 69,000 (PGM2).
• PGM2 forms demonstrated higher catalytic efficiency in phosphoribomutase and glucose 1,6-bisphosphate synthase reactions compared to PGM1 forms.

Conclusions:

• The developed procedure provides a simple and effective method for purifying PGM isozymes from human placenta.
• Human placenta is a suitable tissue for obtaining highly pure PGM isozymes for detailed molecular investigations.
• The purified isozymes share properties with erythrocyte-derived forms, but placenta offers advantages in yield and purity.