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Isomerases

Catalog Product Name EC No. CAS No. Source Price
DIA-432 Beta-Phosphoglucomutase (β-PGM) from E. coli EC 5.4.2.6 E. coli Inquiry
DIA-542 High Purity Phosphoglucose Isomerase EC 5.3.1.9 9001-41-6 Escherichia coli Inquiry
DIA-543 High Purity Phosphomannose Isomerase EC 5.3.1.8 9023-88-5 Escherichia coli Inquiry
DIA-692 Phosphopentomutase (EcDeoB) EC 5.4.2.7 54-2-71 Inquiry
DIA-783 O-Glycopeptidase (IMPa) EC 5.3.1.52 53-1-52 Inquiry
DIA-790 Phosphoglucomutase EC 5.4.2.2 9001-81-4 Inquiry
DIA-892 UDP-Glc 4-Epimerase (GalE) EC 5.1.3.2 9032-89-7 Inquiry
DIA-893 UDP-Glc 4-Epimerase EC 5.1.3.2 9032-89-7 Inquiry
Stereochemical conversion enzymes for analytical and reagent systems

Isomerases

Isomerases rearrange atoms within a molecule without changing its overall elemental composition. In diagnostic assays, they are used when the analyte must be converted into an isomer that a downstream enzyme or detector can recognize.

How isomerases support diagnostic measurement

An isomerase does not simply make a substrate more reactive. It produces a defined stereochemical or structural form, and the rest of the assay must respond selectively to that product. Phosphoglucose isomerase, for example, interconverts glucose-6-phosphate and fructose-6-phosphate, while phosphomannose isomerase acts on a different sugar-phosphate pair. Similar names therefore do not imply interchangeable analytical roles.

Many isomerase reactions are reversible. The observed conversion depends on substrate ratio, cofactor state, pH, temperature, and removal or consumption of the product by the next reaction. A coupled assay should be designed so that the indicator reaction drives or measures the intended direction without becoming the rate-limiting step.

Define both molecular forms: state the starting isomer, the required product, and the reaction that will detect or consume that product.

Analyte conversion

The enzyme converts an analyte into a stereoisomer that can enter a selective colorimetric, fluorometric, or electrochemical reaction.

Coupled metabolic assays

An isomerase can connect a target metabolite to a well-characterized indicator enzyme when direct detection is impractical.

Pathway reconstruction

Defined rearrangement steps help analytical teams reproduce part of a metabolic pathway for research or reagent development.

Substrate discrimination

Stereospecific conversion can distinguish closely related sugars or phosphorylated intermediates when the full reaction chain is selective.

Principal isomerase categories

Choose the enzyme class from the required rearrangement, then confirm the exact substrate pair and reaction direction. Broad class names alone are not sufficient for procurement.

Phosphomutases

Phosphomutases move a phosphate group between positions on the same molecule. They are useful in coupled assays involving phosphorylated sugars and related metabolites.

Check: activator requirements, phosphorylated intermediates, and equilibrium.

Sugar-phosphate isomerases

These enzymes interconvert aldose and ketose forms of phosphorylated sugars, linking an analyte to a compatible downstream detection reaction.

Check: the exact sugar-phosphate pair and direction of measurement.

Epimerases and racemases

Epimerases change configuration at one stereocenter; racemases interconvert enantiomers. Their value depends on strict stereochemical recognition.

Check: stereocenter, cofactor dependence, and side activity.

Intramolecular oxidoreductases

These isomerases redistribute oxidation states within one molecule and may require tightly bound cofactors.

Check: cofactor integrity and redox interference.

Other structural rearrangement enzymes

Ring-opening, ring-closing, and related rearrangements can support specialized carbohydrate or metabolite analysis.

Check: product identity, competing reactions, and analytical confirmation.

Isomerase equilibrium map for coupled diagnosticsFig 1. Isomerase equilibrium map for coupled diagnostics.
(Creative Enzymes Diagnostic)

How to select an isomerase

Evaluate conversion with the intended substrate and the actual indicator system. An activity result obtained with another isomer or a different coupled reaction may not predict assay performance.

Selection factorHow to evaluate itWhy it matters
Substrate and product identitySpecify the complete chemical names, phosphorylation state, and stereochemical configuration of both sides of the reaction.A change in one stereocenter or phosphate position can place the reaction outside the enzyme's useful specificity.
Reaction direction and equilibriumMeasure time courses across the intended substrate range and reagent composition.A reversible reaction may stop before the required conversion unless the product is consumed or the substrate ratio is controlled.
Cofactors and activatorsConfirm metal ions, phosphorylated activators, or bound cofactors in the complete buffer.Insufficient activation can reduce apparent activity; excess cofactor may disturb the indicator reaction.
Coupled-enzyme capacityTitrate the isomerase and downstream enzyme independently and together.The signal should track isomer formation rather than saturation or limitation of the indicator step.
Matrix backgroundUse no-isomerase and no-substrate controls with representative samples.Endogenous enzymes, related isomers, and spontaneous conversion can create blank drift or bias.
Activity method and stabilityCompare candidates with one common functional method and include the planned storage and working hold times.Supplier unit definitions and cofactor states may differ even when nominal concentrations appear similar.

Isomer-form routing matrixFig 2. Isomer-form routing matrix.
(Creative Enzymes Diagnostic)

Selected Creative Enzymes isomerases

Creative Enzymes supplies phosphomutase and sugar-phosphate isomerase products for analytical research and diagnostic reagent development. Select a product name to review its available specifications.

ProductCatalogEC numberSourceActivity
Beta-Phosphoglucomutase (β-PGM) from E. coliDIA-432EC 5.4.2.6E. coli≥ 30 U/mg
High Purity Phosphoglucose IsomeraseDIA-542EC 5.3.1.9Escherichia coli~ 550 U/mg of protein (25 °C, pH 7.6 on fructose 6-phosphate) ~ 649 U/mg of protein (40 °C, pH 7.6 on fructose 6-phosphate)
High Purity Phosphomannose IsomeraseDIA-543EC 5.3.1.8Escherichia coli~ 89 U/mg (25 °C, pH 7.6 on mannose 6-phosphate)

Activity values use product-specific assay definitions. Review the stated method and test conditions before comparing unit values across materials.

Qualifying an isomerase-coupled reaction

Qualification should show that the isomerase, indicator reaction, and sample matrix work as one quantitative system. High activity in an isolated enzyme assay is not enough.

Define the conversion

Document the starting isomer, target product, required direction, analytical range, and acceptable reaction time.

Balance the reaction chain

Determine the enzyme and cofactor concentrations that keep the isomerization step and indicator step within their useful kinetic ranges.

Challenge the matrix

Test representative samples, related isomers, likely interferents, and controls that separate endogenous conversion from reagent activity.

Set material controls

Specify the incoming activity method, cofactor state, formulation limits, storage, lot bridging, and functional release test.

Rate-matching and equilibrium qualification mapFig 3. Rate-matching and equilibrium qualification map.
(Creative Enzymes Diagnostic)

Information to include with an inquiry

Provide the starting and product isomers, reaction direction, concentration range, indicator enzyme and readout, buffer and cofactor composition, sample matrix, required format, scale, and documentation needs.

Frequently asked questions

Why are isomerases often used in coupled assays?

They convert an analyte into a molecular form that an established indicator reaction can measure. The coupled system must still be balanced so that neither step limits the result.

Does reversibility prevent quantitative use?

No. Quantitation is possible when substrate ratios, reaction time, and product consumption keep conversion predictable across the analytical range.

Can two sugar isomerases be substituted for one another?

Only if they act on the same substrate pair with suitable specificity and kinetics. Closely related sugars and phosphate positions often require different enzymes.

How should background conversion be investigated?

Run controls without isomerase, substrate, cofactor, or indicator enzyme, then test related isomers and representative sample matrices.

What does rate matching mean in this context?

The isomerase must form product at a rate the indicator reaction can follow without becoming saturated or limiting the measured response.

What should be included in an incoming specification?

Include the exact substrate pair, activity method, required cofactors or activators, formulation, storage, and an application-level acceptance test.

Selected scientific and institutional references

These sources support the scientific classification and technical selection criteria. Product specifications must be confirmed in current Creative Enzymes documentation.

  1. IUBMB enzyme nomenclature and classification
  2. NC-IUBMB rules for enzyme classification

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For research and industrial use only, not for personal medicinal use.

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