$151.00 - $151.00
Kemptide is a synthetic heptapeptide substrate for cAMP-dependent protein kinase A (PKA). Its sequence, Leu-Arg-Arg-Ala-Ser-Leu-Gly (LRRASLG), contains a well-characterized serine phosphorylation site and has been widely used to measure PKA catalytic activity.
Because Kemptide is short, chemically defined and readily phosphorylated by PKA, it provides a convenient reference substrate for biochemical assays, enzyme kinetics and development of kinase-detection methods.
Product Information
| Property | Specification |
|---|---|
| Product Name | Kemptide |
| CAS No. | 65189-71-1 |
| Sequence | Leu-Arg-Arg-Ala-Ser-Leu-Gly |
| One-Letter Sequence | LRRASLG |
| Peptide Length | 7 amino acids |
| Molecular Weight | Approximately 771.91 Da |
| Molecular Formula | C32H61N13O9 |
| Phosphorylation Site | Ser5 |
| Primary Research Enzyme | Protein kinase A (PKA) |
| Research Areas | Kinase activity, phosphorylation assays, enzyme kinetics, assay development |
PKA Substrate Recognition
The central Arg-Arg-X-Ser arrangement provides a favorable recognition environment for PKA, with Ser5 serving as the phosphate acceptor.
Kemptide has been used extensively as a model substrate for purified PKA catalytic subunits and in assay systems designed to quantify kinase-dependent phosphate transfer.
It should not be interpreted as absolutely selective for PKA under every experimental condition. Related serine/threonine kinases may recognize overlapping substrate motifs, particularly in complex biological samples. We recommend defining the enzyme composition and appropriate controls when substrate phosphorylation is used as a quantitative measure of PKA activity.
Research Applications
Kemptide can support studies of PKA catalytic activity, enzyme kinetics, phosphorylation-dependent mobility shifts, inhibitor screening and development of non-radioactive or affinity-based kinase assays.
For experiments requiring a phosphorylation-deficient reference, the corresponding Kemptide Negative Control replaces the target serine with alanine.
Experimental and Quality Considerations
Quantitative kinase experiments depend on more than peptide purity. Substrate concentration, ATP concentration, divalent-metal conditions, enzyme source and reaction time can all affect the measured phosphorylation rate.
Our Peptide Quality Control capabilities support analytical HPLC and mass spectrometry according to the selected specification.
Frequently Asked Questions
What kinase is Kemptide commonly used to measure?
Kemptide is a well-established substrate for cAMP-dependent protein kinase A (PKA).
Which residue in Kemptide is phosphorylated?
The principal phosphorylation site is Ser5 in the sequence LRRASLG.
Can modified Kemptide substrates be synthesized?
Biotinylation, fluorescent labeling, phosphorylation and sequence variants can be evaluated through Chemical Peptide Synthesis.