biology

Neutrophil elastase

Neutrophil elastase is a biology topic covered in the lgStudy science library. This page brings together a partial reference excerpt, illustrations, worked examples, real-world applications and a short study plan, so you can understand Neutrophil elastase rather than just read about it. In short: Neutrophil elastase (EC 3.4.21.37, leukocyte elastase, ELANE, ELA2, elastase 2, neutrophil, elaszym, serine elastase, subtype human leukocyte elastase (HLE)) is a serine proteinase in the same family as chymotrypsin and has broad substrate specificity. Neutrophil elastase is secreted by neutrophils during inflammation, and destroys bacteria and host tissue.

Key takeaways

Neutrophil elastase belongs to biology; place it in that map before memorising details.
Learn the definition first, then one example that makes the definition concrete.
Connect Neutrophil elastase to a quantity you can measure, compute or draw — that is where exam questions come from.
Reproduce the core statement of Neutrophil elastase from memory before moving on to harder problems.

Reference excerpt

Neutrophil elastase (EC 3.4.21.37, leukocyte elastase, ELANE, ELA2, elastase 2, neutrophil, elaszym, serine elastase, subtype human leukocyte elastase (HLE)) is a serine proteinase in the same family as chymotrypsin and has broad substrate specificity. Neutrophil elastase is secreted by neutrophils during inflammation, and destroys bacteria and host tissue. It also localizes to neutrophil extracellular traps (NETs), via its high affinity for DNA, an unusual property for serine proteases. As with other serine proteinases it contains a charge relay system composed of the catalytic triad of histidine, aspartate, and serine residues that are dispersed throughout the primary sequence of the polypeptide but that are brought together in the three dimensional conformation of the folded protein. The gene encoding neutrophil elastase, ELA2, consists of five exons. Neutrophil elastase is closely related to other cytotoxic immune serine proteases, such as the granzymes and cathepsin G. It is more distantly related to the digestive CELA1. The neutrophil form of elastase (EC 3.4.21.37) is 218 amino acids long, with two asparagine-linked carbohydrate chains (see glycosylation). It is present in azurophil granules in the neutrophil cytoplasm. There appear to be two forms of neutrophil elastase, termed IIa and IIb.

Gene In humans, neutrophil elastase is encoded by the ELANE gene, which resides on chromosome 11.

Function Elastases form a subfamily of serine proteases that hydrolyze many proteins in addition to elastin. Humans have six elastase genes that encode the structurally similar proteins elastase 1, 2, 2A, 2B, 3A, and 3B. Neutrophil elastase hydrolyzes proteins within specialized neutrophil lysosomes, called azurophil granules, as well as proteins of the extracellular matrix following the protein's release from activated neutrophils. Neutrophil elastase may play a role in degenerative and inflammatory diseases by its proteolysis of collagen-IV and elastin of the extracellular matrix. This protein degrades the outer membrane protein A (OmpA) of E. coli as well as the virulence factors of such bacteria as Shigella, Salmonella and Yersinia. Mutations in this gene are associated with cyclic neutropenia (CyN) and severe congenital neutropenia (SCN). At least 95 disease-causing mutations in this gene have been discovered. This gene is clustered with other serine protease gene family members, azurocidin 1 and proteinase 3 genes, at chromosome 19pter. All 3 genes are expressed coordinately and their protein products are packaged together into azurophil granules during neutrophil differentiation.

Clinical significance Neutrophil elastase is an important protease enzyme that when expressed aberrantly can cause emphysema or emphysematous changes. This involves breakdown of the lung structure and increased airspaces. Mutations of the ELANE gene cause cyclic and severe congenital neutropenia, which is a failure of neutrophils to mature. In 2019, a study confirmed that ELANE deletion does not cause neutropenia.

Inhibitors In order to minimize damage to tissues, there are few inhibitors of neutrophil elastase. One group of inhibitors are the Serpins (Serine Protease Inhibitors). Neutrophil elastase has been shown to interact with Alpha 2-antiplasmin, which belongs to the Serpin family of proteins.

Illustrations

Worked examples

Example 1 — a first encounter with Neutrophil elastase

Start with the simplest possible case. Write down what Neutrophil elastase claims or describes in one sentence, then invent the smallest concrete situation in which that sentence is true. In biology, the smallest case is usually a single object, a single equation or a single measurement. Check that every symbol or term in your sentence has a meaning in that case.

Example 2 — changing one variable

Take the situation from Example 1 and change exactly one quantity: double it, halve it, or set it to zero. Predict what should happen to Neutrophil elastase before you calculate. Comparing your prediction with the result is the fastest way to find out whether you understand the idea or only the words.

Example 3 — an exam-style question

Typical questions about Neutrophil elastase ask you to (a) state it precisely, (b) apply it to given data, and (c) explain a limitation. Practise writing all three answers in under five minutes; the third part is what separates a full-mark answer from an average one.

Applications of Neutrophil elastase

In research: Neutrophil elastase appears in biology research whenever the underlying quantities have to be modelled precisely. Papers usually cite it as a starting assumption and then explore where it breaks down.
In technology and industry: Engineering practice reuses Neutrophil elastase in design rules, simulations and safety margins. Knowing the idea lets you read a specification sheet and understand why the numbers look the way they do.
In the classroom: Neutrophil elastase is common in secondary-school and first-year university syllabi. It links to neighbouring topics EC 3.4.21, Extracellular matrix remodeling enzymes, Genes on human chromosome 19, so understanding it makes those chapters shorter.
In everyday life: Look for Neutrophil elastase outside the textbook — in sport, cooking, traffic, electronics or the sky above you. An example you found yourself is remembered far longer than one you were given.

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How to study Neutrophil elastase in 20 minutes

Read the reference excerpt below once, without taking notes.
Close the page and write down what Neutrophil elastase means in your own words.
Compare your version with the excerpt and mark what you missed.
Work through the three examples above with pen and paper.
Explain Neutrophil elastase out loud to somebody else — or to Teacher Smith in the lgStudy chat.

Frequently asked questions

What is Neutrophil elastase in simple terms?

Why does Neutrophil elastase matter?

Because it connects several biology ideas at once: it gives you a definition you can apply, a quantity you can calculate, and a way to check whether a result is plausible.

How should I study Neutrophil elastase?

Read the excerpt, restate it from memory, then work through the examples and applications listed on this page. The five-step study plan above takes about twenty minutes.

What does this page cover?

It gives you a compact reference excerpt plus original lgStudy explanations, examples, applications and study material on Neutrophil elastase.