Smac/Diablo Peptide [AVPIAQKSE], 5-FAM labeled

Product Name: Smac/Diablo Peptide [AVPIAQKSE], 5-FAM labeled

Sequence One Letter Code: AVPIAQKSEK-K(5-FAM)-NH2

Sequence Three Letter Code: H-Ala-Val-Pro-Ile-Ala-Gln-Lys-Ser-Glu-Lys-Lys(5FAM)-NH2

Molecular Weight: 1555.8

Purity: 95%

Form: Lyophilized

Storage Conditions: - 20 °C Protected from light

Research Area: Cancer Disease Research

Source / Species: human

Conjugation: Conjugated

Conjugation Type: Fluorescent dyes

Code Nacres: NA.26

Application: The 5-FAM-Smac/Diablo peptide is a fluorescently labeled peptide corresponding to the N-terminal AVPIAQKSE motif of the mitochondrial protein Smac/Diablo. This sequence antagonizes inhibitor of apoptosis proteins (IAPs), including Livin and XIAP, thereby restoring caspase activity and promoting apoptotic signaling. By disrupting IAP-mediated suppression of apoptosis, the peptide has become an important tool for studying apoptosis regulation and mechanisms of tumor cell survival. The 5-FAM fluorescent label enables real-time visualization, binding assays, and cellular uptake studies using fluorescence-based techniques. This peptide is widely applied in cancer biology, apoptosis research, and drug discovery efforts aimed at overcoming resistance to apoptosis in tumor cells.

Current Research: Apoptosis, or programmed cell death, is an essential biological process responsible for maintaining tissue homeostasis and eliminating damaged or abnormal cells. Disruption of apoptotic pathways is a hallmark of many cancers, allowing tumor cells to evade cell death and continue proliferating. One of the key regulatory systems controlling apoptosis involves inhibitor of apoptosis proteins (IAPs), which suppress caspase activity and block the execution of apoptotic signaling. The 5-FAM-Smac/Diablo peptide is a fluorescently labeled peptide derived from the mitochondrial protein Smac/Diablo that has become a valuable experimental tool for studying this regulatory pathway. This synthetic peptide corresponds to the N-terminal AVPIAQKSE motif of Smac/Diablo, a sequence known for its ability to antagonize IAP proteins such as XIAP (X-linked inhibitor of apoptosis protein) and Livin. By interfering with IAP-mediated inhibition of caspases, the peptide restores apoptotic signaling and enables researchers to investigate the molecular mechanisms controlling cell death. The addition of a 5-FAM (5-carboxyfluorescein) fluorescent label further expands its utility by allowing visualization and detection through fluorescence-based experimental methods. The Role of Smac/Diablo in Apoptosis Regulation Smac/Diablo is a mitochondrial protein released into the cytosol during apoptotic signaling, particularly following mitochondrial outer membrane permeabilization. Once released, Smac/Diablo interacts with IAP proteins that normally inhibit caspases, the proteases responsible for executing apoptosis. IAP family members—including XIAP, cIAP1, cIAP2, and Livin—contain baculovirus IAP repeat (BIR) domains that bind to caspases and suppress their enzymatic activity. This interaction prevents the activation of the apoptotic cascade and promotes cell survival. The N-terminal motif of Smac/Diablo, AVPIAQKSE, binds directly to the BIR domains of IAP proteins. This interaction displaces caspases from IAP binding sites, effectively relieving caspase inhibition and enabling the apoptotic program to proceed. Because of this mechanism, Smac/Diablo functions as an endogenous IAP antagonist that promotes programmed cell death. Design and Features of the 5-FAM-Smac/Diablo Peptide The 5-FAM-Smac/Diablo peptide is designed to replicate the functional N-terminal motif of the Smac/Diablo protein while incorporating a fluorescent reporter. The peptide includes the AVPIAQKSE sequence responsible for binding IAP proteins and antagonizing their inhibitory activity. Attached to the peptide is a 5-FAM fluorophore, a widely used green fluorescent dye. The 5-FAM label provides several experimental advantages: Fluorescent detection of peptide binding and localization Real-time monitoring of peptide–protein interactions Visualization of peptide uptake in cells Quantitative fluorescence assays for screening and analysis Because the fluorescent tag is integrated into the peptide structure, researchers can directly track the peptide in biochemical assays and cellular systems without additional labeling steps. Applications in Apoptosis and Cancer Research The 5-FAM-Smac/Diablo peptide is widely used in apoptosis research and cancer biology to investigate how tumor cells evade programmed cell death. Many cancers overexpress IAP proteins, which suppress caspase activation and enable malignant cells to survive despite cellular stress or therapeutic treatment. By antagonizing IAPs, the Smac/Diablo peptide helps researchers study how restoring caspase activity influences apoptotic pathways. The fluorescent labeling allows investigators to measure peptide binding to IAP proteins and observe its behavior within living cells. Typical applications include: Fluorescence-based binding assays to study interactions between Smac motifs and IAP proteins Cellular uptake studies examining peptide delivery and localization Competition assays investigating inhibitors that target IAP binding sites High-throughput screening for compounds that mimic Smac activity Mechanistic studies of apoptosis signaling pathways These experiments provide valuable insights into how IAP proteins regulate cell death and how their inhibition may influence therapeutic responses. Role in Drug Discovery and Therapeutic Research Because many tumors rely on IAP proteins to suppress apoptosis, targeting the IAP pathway has become an important strategy in anticancer drug development. Small molecules known as Smac mimetics have been developed to replicate the activity of the Smac N-terminal motif and restore apoptotic signaling in cancer cells. The 5-FAM-Smac/Diablo peptide serves as a useful model reagent for evaluating potential Smac mimetics and other apoptosis-modulating compounds. Fluorescence-based assays using this peptide allow researchers to monitor how candidate drugs compete for binding with IAP proteins, helping identify molecules that effectively disrupt IAP–caspase interactions. A Versatile Fluorescent Probe for Apoptosis Studies By combining the biologically active Smac/Diablo motif with a fluorescent 5-FAM label, the 5-FAM-Smac/Diablo peptide offers a powerful experimental platform for studying apoptosis regulation. Its ability to antagonize IAP proteins while enabling fluorescence-based detection makes it especially valuable for mechanistic studies of apoptotic signaling and tumor cell survival. As research continues to explore strategies for restoring apoptosis in cancer cells, tools like the 5-FAM-Smac/Diablo peptide remain essential for understanding IAP biology, caspase regulation, and therapeutic approaches aimed at overcoming resistance to programmed cell death.