ELA1

Related Reading

Pancreatic elastase is extracted from the pancreas of animals with water, and can also be extracted with water at low temperature using bacterial culture. Pancreatic elastase is unique among proteolytic enzymes of animal tissue in that it rapidly hydrolyzes the scleroprotein elastin. Because of its unique specificity in degrading elastin, pancreatic elastase has been implicated in emphysema and atherosclerosis as well as in aging. Pancreatic elastase has also been shown to produce the vascular injury observed in acute pancreatitis.

Structure

Pancreatic elastase is a dense globular protein with a hydrophobic core. The enzyme is formed by three subunits. Each subunit binds a calcium ion. There are three important metal binding sites in amino acids 77, 82, and 87. The catalytic triad at the active site is formed by three hydrogen-bonded amino acid residues (H71, D119, S214), which play a vital role in the cleavage ability of all proteases. It consists of a single peptide chain of 240 amino acids and contains 4 disulfide bonds. It has a high degree of sequence identity with pancreatic elastase, which corresponds to other species (such as rats) and shares 86% of its sequence with the latter. Its enzymatic activity is the result of the specific three-dimensional conformation adopted by its single polypeptide chain. Therefore, its activity will be lost due to denaturation and/or conformational changes.

Figure 1. Structure of pancreatic elastase.

Chemical properties

1. Its appearance is light yellow to dark yellow powder, but also light brown to dark brown liquid. It is soluble in water, insoluble in ethanol, and hygroscopic.
2. Pure pancreatic elastase, a single peptide chain composed of 240 amino acid residues, with a relative molecular mass of about 25,000 and an isoelectric point of 9.5.
3. Elastase can digest and decompose elastin in connective tissue proteins, including peptide bond, amide bond and ester bond for hydrolysis. The optimum pH value for action is 7.8, and the optimum action temperature is 25°C.
4. Elastase has obvious β-lipase effect, which can activate phospholipase A, lower serum cholesterol, improve serum lipids, lower plasma cholesterol and low-density lipoprotein, triglycerides, increase high-density lipoprotein and prevent Lipids deposit on the arterial wall and increase the elasticity of the arteries, and have anti-atherosclerosis and anti-fatty liver effects.
5. Elastase initially exists in the form of zymogen and becomes active after digestion.

Applications

Mutations in the CELA1 gene are suspected to be related to diffuse non-papillary palm plant keratosis (diffuse NEPPK), but the suspected sequence variants are fully functional and not strongly associated with the disease. Recently, specific mutations in the KRT6C gene have been associated with certain conditions of diffuse NEPPK. A possible polymorphism in the CELA1 gene encoding this protein was discovered. At the secondary structure level, this polymorphism manifests itself as the excision of the short CELA1 sequence. The missing sequence carries the key amino acid residues Val-227 and Thr-239, which contribute to the substrate specificity of elastase I (highlighted in Figure 3), and among the eight amino acids involved in the primary contact of elastin. The formation of five (inhibitors)/elastase complexes. These observations suggest that sequence variants may modify the substrate specificity of the enzyme and abolish the binding ability of the inhibitor. Although no obvious pathogenic epidermal abnormalities are associated with truncated ELA1 variants, carriers of the polymorphism may be more likely to develop common skin diseases such as psoriasis and eczema. The role of ELA1 in these common epidermal diseases).

Reference

2. Talas U.; et al. Human elastase 1: evidence for expression in the skin and the identification of a frequent frameshift polymorphism. J. Invest. Dermatol. 2000, 114 (1): 165–70.