science

Glutamyl endopeptidase GluV8

Glutamyl endopeptidase GluV8 is a science 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 Glutamyl endopeptidase GluV8 rather than just read about it. In short: Glutamyl endopeptidase (EC 3.4.21.19, SspA, V8 protease, GluV8, endoproteinase Glu-C, staphylococcal serine proteinase) is an extracellular bacterial serine protease of the glutamyl endopeptidase I family that was initially isolated from the Staphylococcus aureus strain V8. The protease is, hence, commonly referred to as "V8 protease", or alternatively SspA from its corresponding gene.

Key takeaways

Glutamyl endopeptidase GluV8 belongs to science; place it in that map before memorising details.
Learn the definition first, then one example that makes the definition concrete.
Connect Glutamyl endopeptidase GluV8 to a quantity you can measure, compute or draw — that is where exam questions come from.
Reproduce the core statement of Glutamyl endopeptidase GluV8 from memory before moving on to harder problems.

Reference excerpt

Glutamyl endopeptidase (EC 3.4.21.19, SspA, V8 protease, GluV8, endoproteinase Glu-C, staphylococcal serine proteinase) is an extracellular bacterial serine protease of the glutamyl endopeptidase I family that was initially isolated from the Staphylococcus aureus strain V8. The protease is, hence, commonly referred to as "V8 protease", or alternatively SspA from its corresponding gene.

Genetics Glutamyl endopeptidase is in S. aureus expressed from the gene sspA within the operon ssp. Downstream of sspA, the operon also includes the genes of the cysteine protease staphopain B (sspB) and of staphostatin B (sspC; specific inhibitor of staphopain B). Glutamyl endopeptidase is largely co-expressed with the other major proteases of S. aureus: aureolysin, staphopain A, and staphopain B. The transcription of ssp, that occurs via a promoter controlled by "housekeeping" sigma factor σA, is up-regulated by accessory gene regulator agr, while it is repressed by staphylococcal accessory regulator sarA and by alternative sigma factor σB (a stress response modulator of Gram-positive bacteria). ssp expression is highly expressed in post-exponential growth phase. A more complex network of modulators and of environmental conditions affecting ssp expression have been suggested, however. The sspA gene has a high prevalence in the genome of both commensal- and pathogenic-type S. aureus strains.

Activation Glutamyl endopeptidase is expressed as a zymogen that, in order to become fully active, has been modified both through autocatalysis and through cleavage by the metalloprotease aureolysin.

Function Glutamyl endopeptidase proteolytically activates the zymogen of the cysteine protease staphopain B (staphopain A is activated through and independent process). The bacterial protease has a narrow specificity, with a strict preference for catalyzing hydrolysis of proteins after negatively charged amino acids, especially glutamic acid, and to some extent aspartic acid. Aspartic acid is cleaved mainly when followed by a small amino acid, such as glycine. Glutamyl endopeptidase has been shown to cleave certain target proteins among human inflammatory regulators and immune components. It can process kininogen into kinin, and cleave immunoglobulins. The protease also cleaves and inactivates α1-antitrypsin, but is successfully inhibited by α2-macroglubulin. Glutamyl endopeptidase can inhibit the activation of targets within the complement system. It is indicated to cause inhibition to all three pathways of complement activation. Glutamyl endopeptidase can furthermore cleave a wide array bacterial surface proteins, including fibronectin-binding proteins and protein A, potentially acting as a self-regulatory mechanism.

Biological significance An immunization survey of human serum samples suggests that exposure to glutamyl endopeptidase is common, although a correlation to any specific type of infection could not be established. The numerous targets of bacterial proteases, adding the complexity of other virulence factors and their genetic regulation, makes it difficult to attribute a specific role of the protease for the bacteria. In vivo trials with S. aureus with inactivation of ssp or sspA controlling glutamyl endopeptidase gives a contradictory picture for its importance, although it has shown impact for bacterial survival in human whole blood. It has been suggested, however, that the protease promotes S. aureus dissemination through cleavage of self-proteins and through kinin-induced vasodilation, simultaneously protecting against immunological responses, i.e. through corruption of the regulation of the complement system and of neutrophil-derived proteases. Glutamyl endopeptidase is indicated to participate in control and dissemination in bacterial biofilms. The protease can contribute to infection symptoms, e.g. pain and edema through increased vascular permeability by activating kinin. De-regulation of neutrophil proteases through inactivation of α1-antitrypsin has been suggested as a potential cause of dysfunctional coagulation in sepsis.

References

External links Staphylococcus aureus glutamyl+endopeptidase at the U.S. National Library of Medicine Medical Subject Headings (MeSH)

Illustrations

Worked examples

Example 1 — a first encounter with Glutamyl endopeptidase GluV8

Start with the simplest possible case. Write down what Glutamyl endopeptidase GluV8 claims or describes in one sentence, then invent the smallest concrete situation in which that sentence is true. In science, 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 Glutamyl endopeptidase GluV8 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 Glutamyl endopeptidase GluV8 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 Glutamyl endopeptidase GluV8

In research: Glutamyl endopeptidase GluV8 appears in science 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 Glutamyl endopeptidase GluV8 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: Glutamyl endopeptidase GluV8 is common in secondary-school and first-year university syllabi. It links to neighbouring topics EC 3.4.21, Hydrolases, Proteases, so understanding it makes those chapters shorter.
In everyday life: Look for Glutamyl endopeptidase GluV8 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 Glutamyl endopeptidase GluV8 in 20 minutes

Read the reference excerpt below once, without taking notes.
Close the page and write down what Glutamyl endopeptidase GluV8 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 Glutamyl endopeptidase GluV8 out loud to somebody else — or to Teacher Smith in the lgStudy chat.

Frequently asked questions

What is Glutamyl endopeptidase GluV8 in simple terms?

Why does Glutamyl endopeptidase GluV8 matter?

Because it connects several science 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 Glutamyl endopeptidase GluV8?

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 Glutamyl endopeptidase GluV8.