biology

IMP cyclohydrolase

IMP cyclohydrolase 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 IMP cyclohydrolase rather than just read about it. In short: In enzymology, an IMP cyclohydrolase (EC 3.5.4.10) is an enzyme that catalyzes the chemical reaction IMP + H2O ⇌ {\displaystyle \rightleftharpoons } 5-formamido-1-(5-phospho-D-ribosyl)imidazole-4-carboxamide Thus, the two substrates of this enzyme are IMP and H2O, whereas its product is 5-formamido-1-(5-phospho-D-ribosyl)imidazole-4-carboxamide. This enzyme belongs to the family of hydrolases, those acting on carbon…

Key takeaways

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

Reference excerpt

In enzymology, an IMP cyclohydrolase (EC 3.5.4.10) is an enzyme that catalyzes the chemical reaction

IMP + H2O ⇌ {\displaystyle \rightleftharpoons } 5-formamido-1-(5-phospho-D-ribosyl)imidazole-4-carboxamide Thus, the two substrates of this enzyme are IMP and H2O, whereas its product is 5-formamido-1-(5-phospho-D-ribosyl)imidazole-4-carboxamide. This enzyme belongs to the family of hydrolases, those acting on carbon-nitrogen bonds other than peptide bonds, specifically in cyclic amidines. The systematic name of this enzyme class is IMP 1,2-hydrolase (decyclizing). Other names in common use include inosinicase, and inosinate cyclohydrolase. This enzyme catalyses the cyclisation of 5-formylamidoimidazole-4-carboxamide ribonucleotide to IMP, a reaction which is important in de novo purine biosynthesis in archaeal species.

Structural studies In most cases this single-domain protein is arranged to form an overall fold that consists of a four-layered alpha-beta-beta-alpha core structure. The two antiparallel beta-sheets pack against each other and are covered by alpha-helices on one face of the molecule. The protein is structurally similar to members of the N-terminal nucleophile (NTN) hydrolase superfamily. A deep pocket was in fact found on the surface of IMP cyclohydrolase in a position equivalent to that of active sites of NTN-hydrolases, but an N-terminal nucleophile could not be found. Therefore, it is thought that this enzyme is structurally but not functionally similar to members of the NTN-hydrolase family. As of late 2007, 14 structures have been solved for this class of enzymes, with PDB accession codes PDB: 1G8M, PDB: 1M9N, PDB: 1OZ0, PDB: 1P4R, PDB: 1PKX, PDB: 1PL0, PDB: 1THZ, PDB: 2B1G, PDB: 2B1I, PDB: 2IU0, PDB: 2IU3, PDB: 2NTK, PDB: 2NTL, and PDB: 2NTM.

References

Further reading FLAKS JG, ERWIN MJ, BUCHANAN JM (1957). "Biosynthesis of the purines. XVIII 5-Amino-1-ribosyl-4-imidazolecarboxamide 5'-phosphate transformylase and inosinicase". J. Biol. Chem. 229 (2): 603–12. doi:10.1016/S0021-9258(19)63668-9. PMID 13502325.

Illustrations

Worked examples

Example 1 — a first encounter with IMP cyclohydrolase

Start with the simplest possible case. Write down what IMP cyclohydrolase 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 IMP cyclohydrolase 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 IMP cyclohydrolase 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 IMP cyclohydrolase

In research: IMP cyclohydrolase 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 IMP cyclohydrolase 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: IMP cyclohydrolase is common in secondary-school and first-year university syllabi. It links to neighbouring topics EC 3.5.4, EC 3.5 stubs, Enzymes of known structure, so understanding it makes those chapters shorter.
In everyday life: Look for IMP cyclohydrolase 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 IMP cyclohydrolase in 20 minutes

Read the reference excerpt below once, without taking notes.
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Frequently asked questions

What is IMP cyclohydrolase in simple terms?

In enzymology, an IMP cyclohydrolase (EC 3.5.4.10) is an enzyme that catalyzes the chemical reaction IMP + H2O ⇌ {\displaystyle \rightleftharpoons } 5-formamido-1-(5-phospho-D-ribosyl)imidazole-4-carboxamide Thus, the two substrates of this enzyme are IMP and H2O, whereas its product is 5-formamido…

Why does IMP cyclohydrolase 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 IMP cyclohydrolase?

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 IMP cyclohydrolase.