Name: p-Nitrophenyl Phosphate (pNPP)
Brand: Molecular Depot
SKU: B2013804
Price: 495.00 USD
Availability: InStock

<h2>What is ELISA?</h2>
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ELISA, or enzyme-linked immunosorbent assay, is an antibody-based technique that detects and quantifies a specific protein, peptide, antibody, or small molecule in a biological sample by capturing the target on a microplate and generating a measurable signal through an enzyme-substrate reaction. The major formats are sandwich ELISA, using a matched capture and detection antibody pair against different epitopes on the same target, and competitive ELISA, suited to small molecules like hormones that cannot support two simultaneous antibody binding sites.
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<h2 dir="ltr">What you will find: </h2>
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<a href="https://mbpinc.net/reagents/cell-biology/immunology/elisa/elisa-kits" title="ELISA Kits:">ELISA Kits:</a> Fully integrated, pre-coated microplate assays containing factory-matched antibody pairs and standards for rapid, single-target quantification.
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<a href="https://mbpinc.net/reagents/cell-biology/immunology/elisa/elisa-kit-components">ELISA Kit Components:</a> Standalone washing buffers, stop solutions, and high-purity chromogenic substrates to replenish or customize existing assay setups.
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<a href="https://mbpinc.net/reagents/cell-biology/immunology/elisa/bioconjugation-kits" title="Bioconjugation Kits:">Bioconjugation Kits:</a> Precision chemical linking systems engineered to easily attach enzyme reporters or fluorescent tags directly to your primary targeting molecules.
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<h2>How to choose ELISA reagents</h2>
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Decide between a complete kit and building your own assay
A complete kit, available through ELISA Kits, is the faster path for a target with an established commercial option, while ELISA Kit Components are the better choice when developing an assay for a target without an existing kit or customizing one part of an established protocol.
Confirm whether your antibody needs labeling before use
If your capture or detection antibody isn't already conjugated to an enzyme, biotin, or fluorophore, a bioconjugation kit lets you label it yourself in a single tube without a separate purification step, generating a usable conjugate in as little as 15 minutes to a few hours depending on the chemistry.
Match your ELISA format to your target's properties
Sandwich ELISA is the standard choice for most proteins and cytokines, while competitive ELISA is needed for small molecules and haptens too small to bind two antibodies simultaneously.
Check for low molecular weight additives that could interfere with labeling
Common antibody stabilizers like BSA, glycine, and sodium azide contain free amine groups that can be conjugated during a bioconjugation reaction, competing with your target antibody, so confirming your antibody is in a clean, additive-free buffer matters before bioconjugation.
Confirm research-use-only status before any clinical-adjacent application
ELISA kits and components in this category are supplied for research use only and are not validated for in vitro diagnostic applications, so confirming intended use against the product documentation matters before any clinical-adjacent use.
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<h2>Specifications context</h2>
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Antibody bioconjugation reactions exploiting the lysine residue typically complete in 15 minutes to 3 hours depending on the specific chemistry, and the entire labeling reaction can occur within one tube without a separation step for several modern kit formats. As of 2026, single-tube, no-purification bioconjugation chemistry continues to gain adoption over older multi-step labeling protocols, since it reduces hands-on time and antibody loss during the conjugation process.
<a href="https://mbpinc.net/contact-us">Contact the MBP sales desk</a> today to select the ideal microplate assay setup for your target biomolecules.

ELISA

Molecular Depot

Key Specifications

p-Nitrophenyl Phosphate (pNPP)

p-Nitrophenyl Phosphate (pNPP) by Molecular Depot is a p-nitrophenyl phosphate, pNPP, a chromogenic phosphatase substrate. Hydrolysis releases p-nitrophenol, which is yellow in alkaline solution and is measured at 405 nm. It is used as the substrate for alkaline phosphatase in ELISA and in phosphatase activity assays. Each unit contains 250 mg. MBP supplies Molecular Depot immunoassay reagents to research labs in the United States, Canada and worldwide.