Crystallization and preliminary X-ray study of horse pancreatic lipase.

The research article presents findings on the crystallization process and preliminary X-ray study of horse pancreatic lipase (a digestive enzyme) including comparison of some molecular properties with that of the well-studied porcine (pig) pancreatic lipase.

Crystallization of Horse Pancreatic Lipase

• The researchers performed the crystallization of horse pancreatic lipase (EC 3.1.1.3) through the hanging drop method of vapour diffusion, conducted at 20 degrees Celsius. This method typically involves the slow evaporation of solvent to induce crystallization.
• The most successful crystals were developed from an 8 mg/ml solution in 10 to 20% polyethylene glycol 8000, 10 mM-MgCl2, 0.1 M-NaCl, 0.1 M-Mes buffer (pH 5.6).
• The dimensions of the best resulting crystals were 0.8 mm x 0.4 mm x 0.6 mm, indicating a significant size that enables further examination and analysis.

X-Ray Study of Lipase Crystals

• Upon examination with X-ray, the researchers concluded that the lipase crystals were orthorhombic in shape and belong to the space group P2(1)2(1)2(1). The ‘orthorhombic’ term indicates that the 3D crystal shape has a rectangular prism structure with a rhombic base.
• The cell dimensions of the crystals were found to be a = 79.8 A, b = 97.2 A c = 145.3 A. These measurements further confirm the crystal shape and size.
• An asymmetric unit, a basic unit of the crystal structure, was found to contain two molecules of the lipase. The Vm value, a calculated cell volume per protein weight in the crystals, resulted in 2.82 A3/dalton, implying approximately 56% water content in the structure. This volume-to-weight ratio gives insights into crystal packing and solvent content.

Comparison to Porcine Lipase

• The study also briefly compared the properties of the horse pancreatic lipase with the more familiar porcine (pig) pancreatic lipase, although specific comparative details are not mentioned in the abstract.
• Understanding the structural and functional differences between lipases from different species can provide valuable insights into their individual functionality and efficacy as digestive enzymes.

In summary, this study provides valuable information on the successful methods of crystallizing horse pancreatic lipase, its crystal structure, and preliminary comparisons to porcine pancreatic lipase. These findings contribute to the existing pool of knowledge on pancreatic lipases and their variations across species.