engineering

Methylglyoxal synthase

Methylglyoxal synthase 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 Methylglyoxal synthase rather than just read about it. In short: The enzyme methylglyoxal synthase (EC 4.2.3.3) catalyzes the chemical reaction glycerone phosphate ⇌ {\displaystyle \rightleftharpoons } 2-oxopropanal + phosphate Attempts to observe reversibility of this reaction have been unsuccessful. This enzyme belongs to the family of lyases, specifically those carbon-oxygen lyases acting on phosphates.

Key takeaways

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

Reference excerpt

The enzyme methylglyoxal synthase (EC 4.2.3.3) catalyzes the chemical reaction

glycerone phosphate ⇌ {\displaystyle \rightleftharpoons } 2-oxopropanal + phosphate Attempts to observe reversibility of this reaction have been unsuccessful. This enzyme belongs to the family of lyases, specifically those carbon-oxygen lyases acting on phosphates. The systematic name of this enzyme class is glycerone-phosphate phosphate-lyase (methylglyoxal-forming). Other names in common use include methylglyoxal synthetase, and glycerone-phosphate phospho-lyase. This enzyme participates in pyruvate metabolism and is constitutively expressed.

Structural studies

As of late 2007, 7 structures have been solved for this class of enzymes, with PDB accession codes PDB: 1B93, PDB: 1EGH, PDB: 1IK4, PDB: 1S89, PDB: 1S8A, PDB: 1VMD, and PDB: 1WO8. Methylglyoxal synthase (MGS) is a 152-amino acid homohexamer that has a molecular weight of approximately 67,000 kD. The total solvent-accessible surface area of the MGS homohexamer is 18,510 square Angstroms, roughly 40% of the total possible surface area if the subunits were separated. Each monomer consists of five alpha helices surrounding five beta sheets. Of these, two antiparallel beta sheets and one alpha helix are located in a subdomain where the N-terminus and C-terminus are in close juxtaposition. The homohexamer exhibits a threefold axis perpendicular to a twofold axis. Within the wide V-groove, there are twelve hydrogen bonds and six salt bridges between the monomers in the presence of phosphate binding. In the absence of phosphate binding, ten hydrogen bonds and two salt bridges hold the monomers together. At the peak interfaces, ten hydrogen bonds and no salt bridges connect the monomers regardless of phosphate binding. The MGS homohexamer is slightly asymmetrical. All three monomers within the asymmetrical region contain a formate molecule within their respective actives sites. Only one of the monomers within the asymmetrical region is additionally bound to a phosphate. The active site contains many conserved residues for function (Asp, His, Thr) and structure (Gly, Pro). Inorganic phosphate interacts with Lys23, Thr45, Thr47, Thr48, and Gly66. Formate interacts with His19, His98, and Asp71. The active site is exposed to the solvent via a perpendicular channel that consists of Arg150, Tyr146, Asp20, Pro67, His98, and His19. Although mechanistically similar to triosephosphate isomerase (TIM), MGS contains widely dissimilar protein folding that prevents structural alignment with TIM which suggests convergent evolution of their chemical reactions. However, Asp71 in MGS may act similarly to the Glu165, the catalytic base in TIM. Additionally, His19 and His98 may perform the role of the electrophilic catalyst similar to His95 in TIM. CheB methylesterase has the highest structural similarity with MGS.

Mechanism Methylglyoxal synthase is highly specific for DHAP with Km 0.47mM at its optimal pH of 7.5. Contrary to early reports, the purified enzyme does not react with other glycolytic metabolites such as glyceraldehyde-3-phosphate or fructose 1,6-diphosphate. The mechanism of MGS is similar to that of TIM; both enzymes react with dihydroxyacetone phosphate to form an ene-diol phosphate intermediate as the first step of their reaction pathways. However, the second step involves the elimination of phosphate to form methylglyoxal instead of reprotonation to form glyceraldehyde-3-phosphate. The overall reaction is characterized as an intramolecular oxidation-reduction followed by a dephosphorylation. The C-3 of DHAP is oxidized to an aldehyde, while C-1, which bears the phosphate ester, is dephosphorylated and reduced to a methyl group. MGS does not require the use of metal ions or a Schiff base as part of catalysis.

The enzyme first uses Asp71 to specifically abstract the pro-S hydrogen from the C-3 of DHAP to form an ene-diol(ate)-enzyme intermediate, unlike the abstraction of C-3 pro-R hydrogen in TIM by Glu165. A second base deprotonates the hydroxyl group, leading to the collapse of the en-diol(ate) to form the 2-hydroxy 2-propenal enol intermediate along with dissociation of inorganic phosphate (–OPO3) through the cleavage of a C-O bond rather than an O-P bond. This deprotonation is catalyzed by either Asp71 or Asp101. Protonation of the methylene group of the enolate is non-stereospecific. The reaction products are released sequentially with methylglyoxal leaving before the inorganic phosphate. MGS is responsible for the racemic mixture of lactate in cells; the production of methylglyoxal and its further metabolism yields L-(+)-lactate and D-(-)-lactate, while deletion of the MGS gene leads to observation of optically pure D-(-)-lactate.

… excerpt ends here. Continue reading the full article.

Illustrations

Methylglyoxal synthase: Methylglyoxal synthase arrow-pushing mechanism.[11] — Methylglyoxal synthase arrow-pushing mechanism.[11]

Worked examples

Example 1 — a first encounter with Methylglyoxal synthase

Start with the simplest possible case. Write down what Methylglyoxal synthase 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 Methylglyoxal synthase 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 Methylglyoxal synthase 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 Methylglyoxal synthase

In research: Methylglyoxal synthase 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 Methylglyoxal synthase 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: Methylglyoxal synthase is common in secondary-school and first-year university syllabi. It links to neighbouring topics EC 4.2.3, Enzymes of known structure, so understanding it makes those chapters shorter.
In everyday life: Look for Methylglyoxal synthase 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.

Ask Teacher Smith questions about this articleOpens your AI tutor with a question about “Methylglyoxal synthase” →

Affiliate

Preply — study more efficiently by working with a personal tutor. 50% off.

How to study Methylglyoxal synthase in 20 minutes

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

Frequently asked questions

What is Methylglyoxal synthase in simple terms?

The enzyme methylglyoxal synthase (EC 4.2.3.3) catalyzes the chemical reaction glycerone phosphate ⇌ {\displaystyle \rightleftharpoons } 2-oxopropanal + phosphate Attempts to observe reversibility of this reaction have been unsuccessful. This enzyme belongs to the family of lyases, specifically tho…

Why does Methylglyoxal synthase 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 Methylglyoxal synthase?

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 Methylglyoxal synthase.