Solid-phase enzyme modification via affinity chromatography.

Area of Science:

• Biochemistry
• Enzyme Engineering
• Pharmacology

Background:

• L-asparaginase (ASNase) is a crucial antileukemic enzyme.
• Native ASNase can cause adverse effects and has a short circulation time.
• Enzyme modification is a strategy to improve therapeutic properties.

Purpose of the Study:

• To modify L-asparaginase (ASNase) with activated polyethylene glycol (PEG).
• To evaluate the impact of PEGylation on ASNase activity and stability.
• To assess the in vivo performance of PEGylated ASNase in terms of circulation time and immunogenicity.

Main Methods:

• Solid-phase modification of ASNase using activated polyethylene glycol (PEG(2)) via ligand-immobilized affinity columns.
• Characterization of PEGylated ASNase, including specific activity and PEG conjugation.
• Sequential modification with heparin.
• Intravenous administration of PEGylated ASNase in presensitized mice to assess pharmacokinetics and anaphylaxis.

Main Results:

• Modification of ASNase for 1 hour yielded PEGylated ASNase with 50.2% specific activity recovery and 69 PEG(2) molecules per ASNase molecule.
• Sequential modification resulted in approximately nine heparin molecules per PEGylated ASNase molecule.
• PEGylated ASNase exhibited prolonged blood circulation in mice.
• No adverse effects or anaphylaxis symptoms were observed in presensitized mice after administration of PEGylated ASNase.

Conclusions:

• Solid-phase PEGylation is an effective method for modifying ASNase.
• PEGylated ASNase demonstrates improved pharmacokinetic properties and reduced immunogenicity.
• This modified enzyme holds promise for enhanced antileukemic therapy with fewer side effects.