biology

Mitochondrial peptide methionine sulfoxide reductase

Mitochondrial peptide methionine sulfoxide reductase 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 Mitochondrial peptide methionine sulfoxide reductase rather than just read about it. In short: Mitochondrial peptide methionine sulfoxide reductase, also known as methionine sulfoxide reductase A, is an enzyme that in humans is encoded by the MSRA gene. MRSA is a member of the methionine sulfoxide reductase (Msr) family of enzymes.

Key takeaways

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Reference excerpt

Mitochondrial peptide methionine sulfoxide reductase, also known as methionine sulfoxide reductase A, is an enzyme that in humans is encoded by the MSRA gene. MRSA is a member of the methionine sulfoxide reductase (Msr) family of enzymes.

Function Msr is ubiquitous and highly conserved. Human and animal studies have shown the highest levels of expression in kidney and liver. It carries out the enzymatic reduction of methionine sulfoxide (MetO), the oxidized form of the amino acid methionine (Met), back to methionine, using thioredoxin to catalyze the enzymatic reduction and repair of oxidized methionine residues. Its proposed function is thus the repair of oxidative damage to proteins to restore biological activity. Oxidation of methionine residues in tissue proteins can cause them to misfold or otherwise render them dysfunctional.

Clinical significance MetO increases with age in body tissues, which is believed by some to contribute to biological ageing. Moreover, levels of methionine sulfoxide reductase A (MsrA) decline in aging tissues in mice and in association with age-related disease in humans. There is thus a rationale for thinking that by maintaining the structureincreased levels or activity of MsrA might retard the rate of aging. Indeed, transgenic Drosophila (fruit flies) that overexpress methionine sulfoxide reductase show extended lifespan. However, the effects of MsrA overexpression in mice were ambiguous. MsrA is found in both the cytosol and the energy-producing mitochondria, where most of the body's endogenous free radicals are produced. Transgenically increasing the levels of MsrA in either the cytosol or the mitochondria had no significant effect on lifespan assessed by most standard statistical tests, and may possibly have led to early deaths in the cytosol-specific mice, although the survival curves appeared to suggest a slight increase in maximum (90%) survivorship, as did analysis using Boschloo's test, a binomial test designed to test greater extreme variation. Deletion of this gene has been associated with insulin resistance in mice, while overexpression reduces insulin resistance in old mice.

See also MSRB2 Methionine oxidation SEPX1

References

Illustrations

Worked examples

Example 1 — a first encounter with Mitochondrial peptide methionine sulfoxide reductase

Start with the simplest possible case. Write down what Mitochondrial peptide methionine sulfoxide reductase 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 Mitochondrial peptide methionine sulfoxide reductase 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 Mitochondrial peptide methionine sulfoxide reductase 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 Mitochondrial peptide methionine sulfoxide reductase

In research: Mitochondrial peptide methionine sulfoxide reductase 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 Mitochondrial peptide methionine sulfoxide reductase 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: Mitochondrial peptide methionine sulfoxide reductase is common in secondary-school and first-year university syllabi. It links to neighbouring topics Genes on human chromosome 8, Human chromosome 8 gene stubs, so understanding it makes those chapters shorter.
In everyday life: Look for Mitochondrial peptide methionine sulfoxide reductase 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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Frequently asked questions

What is Mitochondrial peptide methionine sulfoxide reductase in simple terms?

Why does Mitochondrial peptide methionine sulfoxide reductase 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 Mitochondrial peptide methionine sulfoxide reductase?

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 Mitochondrial peptide methionine sulfoxide reductase.