Eglin c, a pharmacologically active elastase inhibitor

Area of Science:

• Biochemistry
• Pharmacology
• Biotechnology

Background:

• Eglin c is a potent elastase/cathepsin G inhibitor isolated from the medicinal leech Hirudo medicinalis.
• The gene encoding Eglin c was synthesized, cloned, and expressed in E. coli, enabling biotechnological production.

Purpose of the Study:

• To characterize the biochemical and pharmacological properties of Eglin c.
• To compare the inhibitory kinetics of Eglin c with naturally occurring proteinase inhibitors.
• To evaluate the efficacy of Eglin c in a preclinical model of emphysema.

Main Methods:

• Determined the rate of complex formation between Eglin c and human leukocyte elastase (HLE) or human cathepsin G (H. Cat. G).
• Compared association rate constants with alpha 1-proteinase inhibitor (alpha 1 PI) and alpha 2-macroglobulin (alpha 2M).
• Assessed Eglin c's protective effect against HLE-induced emphysema in a hamster model following intratracheal administration.

Main Results:

• Eglin c exhibited association rate constants comparable to natural inhibitors like alpha 1 PI and alpha 2M.
• Identical association rate constants were observed for both leech-extracted and biotechnologically produced Eglin c with HLE.
• Equilibrium inhibition constants (Ki) for Eglin c/HLE and Eglin c/H. Cat. G interactions were in the order of 10(-10) M.
• Intratracheal administration of Eglin c one hour prior to HLE insult completely prevented emphysema in hamsters.

Conclusions:

• Biotechnologically produced Eglin c demonstrates potent and comparable inhibitory activity to its naturally occurring counterpart.
• Eglin c effectively prevents HLE-induced emphysema in a preclinical model.
• Eglin c shows a favorable safety profile with no observed toxicity in the emphysema model.