What is calb lipase?
CalB is lipase B from the yeast historically named Candida antarctica. It is a widely studied biocatalyst for selective ester transformations and is frequently used in immobilised form.
CalB is a particular lipase, not a generic name for all Candida or fungal lipases. CalA and CalB have different structures and substrate preferences.
The key idea
CalB selectivity is a property of the substrate–enzyme–medium combination, not an unconditional label.
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Core properties and EC classification
An EC number classifies a catalysed reaction. It does not specify a production strain, amino-acid sequence, preparation purity or operating optimum. Related proteins can perform the same classified reaction, while a commercial activity name may cover several reactions.
· Classification · Accepted activity · Reaction scope
· EC 3.1.1.3 · triacylglycerol lipase · triacylglycerol + H 2 O = diacylglycerol + a carboxylate
· Substrate / system · Chemical distinction · Practical interpretation
· Hydrolysis · Water resolves the intermediate · Ester cleavage
· Esterification/transesterification · Alcohol acceptor participates · Ester synthesis or exchange
· Immobilised CalB · Protein associated with a carrier · Carrier mass is not enzyme molecular mass
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Molecular weight: monomer, dimer or multimer?
A monomer contains one protein subunit; a homodimer contains two copies of the same subunit, and a higher oligomer contains more. A protein domain is a region within a chain, not an additional subunit. Likewise, mixing enzymes in a bottle does not establish that they form a stable molecular complex.
· Property of the named example · Evidence and interpretation
· Molecular weight of the example · Approximately 33.0 kDa for the deposited protein entity (one polypeptide; PDB 1TCA). This is not whole-formulation mass or a measured glycosylated mass.
· Monomer, dimer or multimer? · Monomer, as annotated for PDB 1TCA biological assembly 1.
· Model and experimental resolution · PDB 1TCA; 1.55 Å X-ray diffraction; representative chain A.
· Deposited protein sequence · 317 residues in the experimental entity; unresolved coordinates and biological processing are separate considerations.
The mass above is the deposited polypeptide-entity value. Glycosylation, precursor processing, linkers or omitted domains can change the experimentally observed mass. SDS–PAGE primarily informs denatured subunit size; native assembly needs evidence such as SEC–MALS, analytical ultracentrifugation or an appropriate structural analysis. The viewer shows one selected chain for clarity, not necessarily the complete biological assembly.
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FROM MOLECULE TO APPLICATIONCalB selectivity is a property of the substrate–enzyme–medium combination, not an unconditional label.
Natural sources and fermentation hosts
The natural donor is Candida antarctica, a name retained in the enzyme abbreviation and structural literature. CalB is distinct from lipase A from the same organism.
Industrial CalB can be produced by recombinant microbial fermentation, including fungal or yeast expression systems. The manufacturing host may therefore differ from the natural donor. Immobilisation carrier and enzyme loading should be specified separately.
· Term · What it means in this report
· Natural donor of the model · Candida antarctica — the organism associated with the displayed protein sequence.
· Expression host of the structural sample · Not separately specified in this structural record; do not infer a recombinant host.
· Manufacturing route · Industrial CalB can be produced by recombinant microbial fermentation, including fungal or yeast expression systems. The manufacturing host may therefore differ from the natural donor. Immobilisation carrier and enzyme loading should be specified separately.
· Supplied product · Use the linked product documentation for the actual grade, activity assay and declared source. A structural example does not establish the manufacturing organism or purity of the supplied preparation.
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Reaction mechanism and structure–function relationships
CalB uses a serine–histidine–aspartate catalytic triad and a covalent acyl intermediate. Water favours hydrolysis; suitable alcohol acceptors and controlled water activity enable transesterification or esterification. Its active-site architecture differs from strongly lid-gated lipases, so classical interfacial activation should not be assumed. Enantioselectivity depends on substrate and conditions, not simply the CalB name.
THE REACTION, STEP BY STEP
1
Bind a suitable ester or acyl donor
2
Form the catalytic serine acyl intermediate
3
Resolve it with water or a compatible alcohol acceptor
Ester + water or alcohol→Hydrolysis or transesterification products
Conceptual reaction pathway; the stages describe function rather than atomic geometry.
From active-site chemistry to a useful process
CalB selectivity is a property of the substrate–enzyme–medium combination, not an unconditional label. Report solvent, water-control method and catalyst basis explicitly. Compare successive reuse cycles at equal reaction times, measuring product formation rather than assuming that recovered carrier mass represents retained catalytic activity.
The catalytic mechanism explains which chemical transformation is possible. It does not, by itself, establish the rate in a complex material. Substrate presentation, reaction-medium composition and retention of the active fold determine whether that chemistry can proceed usefully under the chosen conditions. This is why a defined-substrate activity measurement and an application trial provide complementary evidence.
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Discovery and scientific milestones
Discovery, purification, structural characterisation and industrial adoption are different historical milestones. The named studies below identify specific contributions; a publication date is not automatically the first discovery of every activity covered by the enzyme name.
Foundations
Biochemical and historical context
The crystallographic study associated with PDB 1TCA established a molecular view of Candida antarctica lipase B. Its significance is the relationship between a defined protein fold and substrate access, rather than discovery of all lipase activity. The organism name used historically in CalB literature remains part of the established enzyme name.
[3]1994
Uppenberg and colleagues: molecular characterisation
The primary study associated with PDB 1TCA is “The sequence, crystal structure determination and refinement of two crystal forms of lipase B from Candida antarctica.”. The experimental structure links the named protein to a concrete molecular model, allowing its fold, substrate-binding region and assembly to be examined rather than inferred from the general enzyme name.
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Major industrial applications and research uses
Fine-chemical and chiral synthesis, ester production and lipid modification exploit CalB selectivity. Repeated use of immobilised enzyme can be attractive, but carrier stability, solvent effects and substrate diffusion influence operational performance.
01
Fine-chemical synthesis
Exploit compatible ester chemistry.
Measure success: Measure conversion and impurity profile.
02
Chiral transformations
Investigate selective conversion.
Measure success: Determine enantiomeric composition experimentally.
03
Reusable catalysts
Retain enzyme on a suitable support.
Measure success: Track recovered activity across cycles.
A research use, a development-stage process and an established commercial application do not imply the same level of readiness. Match the preparation to the target matrix and required grade, then validate the specific outcome described above. The product links below provide the route from this scientific overview to a defined supplied formulation.
Activity assays and interpreting experimental results
Measure conversion and product selectivity chromatographically. For chiral work, report enantiomeric composition and conversion together. Specify solvent, water activity, temperature and immobilised or soluble form; a hydrolysis unit alone may not predict synthetic performance.
A useful experiment for this enzyme
Report solvent, water-control method and catalyst basis explicitly. Compare successive reuse cycles at equal reaction times, measuring product formation rather than assuming that recovered carrier mass represents retained catalytic activity.
· Experimental question · Evidence to collect
· Is the enzyme active? · Measure an initial rate with a defined substrate, blank correction and a stated activity-unit definition.
· Does it work on this material? · Measure conversion and impurity profile.
· Is the preparation stable? · Measure residual activity after a specified exposure, separately from activity during the exposure.
· Is the product what you intended? · Determine enantiomeric composition experimentally.
Keep enzyme loading, substrate amount, mixing, temperature and sampling time explicit. Use a no-enzyme control to capture non-enzymatic changes and a suitable analytical blank for colour, background sugars, peptides or other interfering components. A time course is more informative than one endpoint when the reaction slows, because substrate depletion, loss of activity and product effects can produce similar plateaus.
Reading kinetic and operating data
Compare reported pH and temperature optima only when substrate and assay duration are comparable. An optimum describes the measured rate within an experiment; it is not a guarantee of long-incubation stability. For heterogeneous substrates, changes in accessibility can also affect apparent kinetic behaviour. Cite the protein, substrate and conditions alongside any kinetic constant rather than treating it as a universal property of the enzyme name.
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Common questions
Does every CalB reaction give high enantioselectivity?
No. Substrate fit and reaction conditions determine selectivity.
Does dry solvent mean the enzyme needs no water?
Enzyme hydration and reaction water balance are separate considerations.
Can carrier mass be used as the protein molecular weight?
No. Immobilisation adds a material support, not protein subunits.
Continue exploring
CalB for Esterification and Transesterification: A Trial Guide ↗Lipase deep dive ↗Cutinase deep dive ↗Phospholipase deep dive ↗
