engineering

Sulfiredoxin

Sulfiredoxin is a engineering 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 Sulfiredoxin rather than just read about it. In short: In enzymology, a sulfiredoxin (EC 1.8.98.2) is an enzyme that catalyzes the chemical reaction peroxiredoxin-(S-hydroxy-S-oxocysteine) + ATP + 2 R-SH ⇌ {\displaystyle \rightleftharpoons } peroxiredoxin-(S-hydroxycysteine) + ADP + phosphate + R-S-S-R The 3 substrates of this enzyme are peroxiredoxin-(S-hydroxy-S-oxocysteine), ATP, and a thiol, whereas its 4 products are peroxiredoxin-(S-hydroxycysteine), ADP, phosphat…

Key takeaways

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

Reference excerpt

In enzymology, a sulfiredoxin (EC 1.8.98.2) is an enzyme that catalyzes the chemical reaction

peroxiredoxin-(S-hydroxy-S-oxocysteine) + ATP + 2 R-SH ⇌ {\displaystyle \rightleftharpoons } peroxiredoxin-(S-hydroxycysteine) + ADP + phosphate + R-S-S-R The 3 substrates of this enzyme are peroxiredoxin-(S-hydroxy-S-oxocysteine), ATP, and a thiol, whereas its 4 products are peroxiredoxin-(S-hydroxycysteine), ADP, phosphate, and a disulfide. This enzyme is involved in antioxidant metabolism by re-activating peroxiredoxins, which are a group of peroxidases, when these enzymes are inhibited by over-oxidation. This enzyme belongs to the family of oxidoreductases, specifically those acting on a sulfur group of donors with other, known, acceptors. The systematic name of this enzyme class is peroxiredoxin-(S-hydroxy-S-oxocysteine):thiol oxidoreductase [ATP-hydrolysing; peroxiredoxin-(S-hydroxycysteine)-forming]. Other names in common use include Srx1, sulphiredoxin, and peroxiredoxin-(S-hydroxy-S-oxocysteine) reductase.

Function The sulfur atom in the side-chain of the amino acid cysteine can exist in several different oxidation states. The most reduced of these is as a thiol group (Cys-SH). Oxidation of cysteine produces cystine, which is one half of a disulfide bond (Cys-S-S-Cys). These lower oxidation states of cysteine (disulfides) are readily reversible, but higher oxidation states, such as sulfinic acid (Cys-SOOH), were once considered irreversible, biologically speaking. This view changed with the discovery of sulfiredoxin, an enzyme that can reduce sulfinic acid back to thiol, in an ATP-dependent manner. Additional work suggests that it plays a role in resolving mixed disulfide bonds. Initially discovered in yeast, sulfiredoxin is conserved in all eukaryotes, including mammals. In a perfect example of how multiple gene names can confuse the field, sulfiredoxin (Srxn1) was already known as a gene of unknown function, cloned by differential display of an in vitro model of tumorigenesis, and termed “Neoplastic progression 3/Npn3” although nothing about its actual function was reported. As a result, in most mouse microarray studies, sulfiredoxin is termed neoplastic progression 3, and typically classified as “cancer related” or “other” rather than as “antioxidant”. Npn3/Srxn1 is upregulated by an exceptionally large fold-magnitude in microarray studies of oxidative stress. Npn3/Srxn1 is induced up to 32-fold by D3T (liver), 12-fold by CdCl2, (liver), 4- to 10-fold by paracetamol (liver) and 3.3-fold by paraquat (heart). A survey of the GEO database also indicates a large induction of Npn3/Srxn1 is observed in injury to the lung by hyperoxia (data set GDS247, ID# 102780_at) or phosgene (GDS1244, 1451680_at). That Npn3 and Sxrn1 are synonyms of the same gene has not been pointed out in any of the 15 papers written on Srxn1 since its discovery. Because it was discovered so recently, the function of sulfiredoxin is not yet fully known. Sulfiredoxin knockout mice is available in Dr. Qiou Wei's lab at University of Kentucky and mice are found normal under normal circumstances. On treatment of these mice with carcinogens, Srx knockout mice were found to be less prone to few cancer types compared to wildtype mice. It shows the critical role of Srx in carcinogenesis of human tumors.

References

Biteau B, Labarre J, Toledano MB (2003). "ATP-dependent reduction of cysteine-sulphinic acid by S. cerevisiae sulphiredoxin". Nature. 425 (6961): 980–4. Bibcode:2003Natur.425..980B. doi:10.1038/nature02075. PMID 14586471. S2CID 2804619. Chang TS, Jeong W, Woo HA, Lee SM, Park S, Rhee SG (2004). "Characterization of mammalian sulfiredoxin and its reactivation of hyperoxidized peroxiredoxin through reduction of cysteine sulfinic acid in the active site to cysteine". J. Biol. Chem. 279 (49): 50994–1001. doi:10.1074/jbc.M409482200. PMID 15448164. Woo HA, Jeong W, Chang TS, Park KJ, Park SJ, Yang JS, Rhee SG (2005). "Reduction of cysteine sulfinic acid by sulfiredoxin is specific to 2-cys peroxiredoxins". J. Biol. Chem. 280 (5): 3125–8. doi:10.1074/jbc.C400496200. PMID 15590625. Findlay, V. J., Townsend, D. M., Morris, T. E., Fraser, J. P., He, L. and Tew, K. D. (2006) A novel role for human sulfiredoxin in the reversal of glutathionylation. Cancer Res. 66, 6800-6806 Sun, Y., Hegamyer, G. and Colburn, N. H. (1994) Molecular cloning of five messenger RNAs differentially expressed in preneoplastic or neoplastic JB6 mouse epidermal cells: one is homologous to human tissue inhibitor of metalloproteinases-3. Cancer Res. 54, 1139–1144 Kwak, M. K., Wakabayashi, N., Itoh, K., Motohashi, H., Yamamoto, M. and Kensler, T. W. (2003) Modulation of gene expression by cancer chemopreventive dithiolethiones through the Keap1-Nrf2 pathway. Identification of novel gene clusters for cell survival. J. Biol. Chem. 278, 8135-8145 Wimmer, U., Wang, Y., Georgiev, O. and Schaffner, W. (2005) Two major branches of anti-cadmium defense in the mouse: MTF-1/metallothioneins and glutathione. Nucleic Acids Res 33, 5715-5727 Welch, K. D., Reilly, T. P., Bourdi, M., Hays, T., Pise-Masison, C. A., Radonovich, M. F., Brady, J. N., Dix, D. J. and Pohl, L. R. (2006) Genomic identification of potential risk factors during acetaminophen-induced liver disease in susceptible and resistant strains of mice. Chem Res Toxicol 19, 223-233 Edwards, M. G., Sarkar, D., Klopp, R., Morrow, J. D., Weindruch, R. and Prolla, T. A. (2003) Age-related impairment of the transcriptional responses to oxidative stress in the mouse heart. Physiol Genomics 13, 119-127

Worked examples

Example 1 — a first encounter with Sulfiredoxin

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

In research: Sulfiredoxin appears in engineering 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 Sulfiredoxin 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: Sulfiredoxin is common in secondary-school and first-year university syllabi. It links to neighbouring topics EC 1.8.98, Enzymes of unknown structure, so understanding it makes those chapters shorter.
In everyday life: Look for Sulfiredoxin 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 Sulfiredoxin in 20 minutes

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

Frequently asked questions

What is Sulfiredoxin in simple terms?

In enzymology, a sulfiredoxin (EC 1.8.98.2) is an enzyme that catalyzes the chemical reaction peroxiredoxin-(S-hydroxy-S-oxocysteine) + ATP + 2 R-SH ⇌ {\displaystyle \rightleftharpoons } peroxiredoxin-(S-hydroxycysteine) + ADP + phosphate + R-S-S-R The 3 substrates of this enzyme are peroxiredoxin…

Why does Sulfiredoxin matter?

Because it connects several engineering 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 Sulfiredoxin?

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 Sulfiredoxin.