Name: PKA Inhibitor (5-24)
Brand: Molecular Depot
SKU: B2017239
Price: 695.00 USD
Availability: InStock

<h2>What are biochemical enzyme inhibitors?</h2>
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Biochemical enzyme inhibitors in this category are chemical compounds that block the activity of specific enzyme classes during sample preparation, cell lysis, or biochemical assays, the most critical of which are protease inhibitors that prevent endogenous proteases from degrading your protein of interest after cell disruption, and phosphatase inhibitors that preserve post-translational phosphorylation modifications that would otherwise be rapidly removed after lysis. Kinase inhibitors and other enzyme class inhibitors are also relevant for maintaining specific cellular states during extraction.
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<h2 dir="ltr">What you will find:</h2>
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PMSF Protease Blockers: High-potency Phenylmethylsulfonyl Fluoride compounds engineered to halt serine proteases during tissue extraction.
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Phosphatase Inhibitor Cocktails: Specialized chemical blends optimized to preserve the phosphorylation state of proteins during cell lysis.
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Broad-Spectrum Protease Cocktails: Ready-to-use formulation mixes designed for comprehensive protection against a wide range of digestive enzymes.
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Reversible Kinase Inhibitors: Highly selective small molecules prepared for targeted signaling pathway inhibition and enzyme mechanism mapping.
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<h2>How to choose and use enzyme inhibitors</h2>
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Add protease inhibitors to lysis buffer immediately before use
Protease inhibitors must be added to cell lysis buffer immediately before use, since most inhibitors, particularly PMSF, hydrolyze rapidly in aqueous solution and lose activity quickly. Pre-making a lysis buffer with inhibitors hours or days in advance results in inactive inhibitor and unprotected protein.
Choose a protease inhibitor cocktail for broad-spectrum coverage
Protease inhibitor cocktails combine multiple inhibitors with different mechanisms and specificities, typically covering serine proteases, cysteine proteases, aspartic proteases, and metalloproteases in a single formulation. Using a cocktail rather than a single inhibitor reduces the risk of leaving any protease class uninhibited during protein extraction.
Understand PMSF's specific handling requirements
PMSF (phenylmethylsulfonyl fluoride) is a broad serine protease inhibitor that is highly effective but hydrolyzes in aqueous solution with a half-life of approximately 30 minutes at pH 7, requiring addition directly to lysis buffer immediately before use. It is also acutely toxic and must be handled with appropriate precautions.
Include phosphatase inhibitors when studying phosphorylation
Phosphatase inhibitors, including sodium orthovanadate (Tyr phosphatase inhibitor) and sodium fluoride (Ser/Thr phosphatase inhibitor), must be included in lysis buffer when extracting proteins for phosphorylation studies, since cellular phosphatases rapidly dephosphorylate substrates after cell disruption unless inhibited.
Be aware that some inhibitors interfere with downstream assays
EDTA in protease inhibitor cocktails chelates divalent metal ions and inhibits metalloproteases, but also inhibits zinc- and magnesium-dependent enzymes that you may need downstream, and can interfere with immunoprecipitation by chelating zinc ions required for protein A/G binding. Choosing an EDTA-free cocktail avoids this interference when needed.
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<h2>Specifications context</h2>
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PMSF hydrolyzes in aqueous solution at pH 7 with a half-life of approximately 30 minutes, meaning it must be prepared as a concentrated stock in a non-aqueous solvent, typically isopropanol or ethanol, and added directly to lysis buffer immediately before use. As of 2026, pre-formulated protease and phosphatase inhibitor cocktail tablets or mini-tablets that dissolve in a defined volume of lysis buffer remain the most widely adopted format for routine protein extraction, providing broad-spectrum coverage without the handling challenges of individual inhibitor stocks.
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Enzyme Inhibitors

Molecular Depot

Key Specifications

PKA Inhibitor (5-24)

PKA Inhibitor (5-24) by Molecular Depot is a synthetic peptide inhibitor of protein kinase A (PKA), corresponding to amino acids 5 to 24 of the heat-stable protein kinase inhibitor (PKI). PKA phosphorylates target proteins in response to raised cyclic AMP. It is used to inhibit PKA selectively in cell-free assays, permeabilised cells and microinjection experiments. Each unit contains 500 µg. MBP supplies Molecular Depot research reagents to research labs in the United States, Canada and worldwide.