BAC Water (Bacteriostatisch Water)<\/strong><\/a> \u2014 30 mL multi-dose vial, 0.9% benzyl-alcohol-preserved, USP-grade.<\/div>\nOpslag en Reconstituering<\/h2>\n
Voor reconstituering:<\/strong> store lyophilized vials refrigerated at 2\u20138 \u00b0C in original packaging for short-term working stock. For long-term storage, freeze unopened vials at \u221220 \u00b0C. Lyophilized LL-37 is stable under refrigeration for up to 24 months and at \u221220 \u00b0C for up to 36 months. Avoid freeze-thaw cycles of the lyophilized powder. Like all cationic AMPs, LL-37 is prone to plastic adsorption<\/strong> \u2014 even small losses to standard polypropylene tubes can confound dose-response data. Use low-binding tubes (siliconised glass, Protein LoBind, or polypropylene pre-coated with bovine serum albumin) for stock storage and serial dilutions in low-protein assay buffers.<\/p>\nReconstitueringsprocedure:<\/strong> inject bacteriostatic water down the side wall of the vial (not directly onto the lyophilized cake). For a 5 mg vial, 1.0 mL of bacteriostatic water yields a 5 mg\/mL working concentration; 2.0 mL yields a 2.5 mg\/mL working stock. Swirl gently \u2014 do not vortex aggressively, as foaming entrains air and can disrupt helix folding. Allow the powder to dissolve fully (typically 1\u20132 minutes) before withdrawing. For applications sensitive to bacteriostatic agents (cell-culture experiments), reconstitute in sterile water or 0.01% acetic acid. Once reconstituted, store the vial at 2\u20138 \u00b0C and use within 14\u201328 days. Protect from light. Discard if cloudiness, particulates, or colour change appears.<\/p>\nVeelgestelde vragen<\/h2>\nIs LL-37 the same as cathelicidin?<\/h3>\n
LL-37 is the active C-terminal 37-amino-acid peptide released from human cathelicidin (the inactive proform hCAP-18, encoded by the CAMP gene). Cathelicidin is the family name and refers across many vertebrate species; LL-37 is the specific name of the active human cathelicidin peptide. Other names you may see in the literature \u2014 CAP-18 and FALL-39 \u2014 refer to the same molecule from different historical naming conventions.<\/p>\n
How is LL-37 different from defensins?<\/h3>\n
LL-37 and the defensins (\u03b1- and \u03b2-defensins) are the two main families of mammalian antimicrobial peptides. Defensins are smaller, cysteine-rich, and adopt \u03b2-sheet structures stabilised by 3 disulfide bonds. LL-37 is a longer linear cationic peptide that adopts an amphipathic \u03b1-helix in membrane environments \u2014 with no disulfide bridge. Both classes share broad antimicrobial activity and immunomodulatory roles but operate through structurally distinct mechanisms.<\/p>\n
What is the typical effective concentration of LL-37 in antimicrobial assays?<\/h3>\n
Published minimum inhibitory concentrations (MICs) for LL-37 against susceptible Gram-positive and Gram-negative pathogens generally range from 1 to 32 \u00b5g\/mL depending on strain, assay buffer ionic strength, and biofilm vs planktonic format. Higher concentrations (50\u2013100 \u00b5g\/mL) are commonly used for direct membrane-disruption studies and biofilm-eradication assays. Immunomodulatory readouts (chemotaxis, LPS neutralisation, keratinocyte migration) typically use much lower concentrations (0.5\u201310 \u00b5g\/mL). Determine dose ranges from peer-reviewed literature appropriate to your specific protocol.<\/p>\n
Why does plastic adsorption matter for LL-37?<\/h3>\n
Cationic AMPs like LL-37 can adsorb significantly to standard polypropylene and polystyrene labware surfaces, especially in low-protein buffers. Losses of 30\u201380% to a single tube transfer have been documented in the literature for cationic peptides at low concentrations. This can produce systematic under-estimation of activity, particularly in dilution series for MIC determination. Use low-binding tubes, pre-coat tubes with BSA, or include carrier protein in dilution buffers as appropriate to the assay readout.<\/p>\n
How does LL-37 distinguish microbial from mammalian membranes?<\/h3>\n
The selectivity arises from membrane composition. Microbial membranes (especially Gram-negative outer membranes and Gram-positive cytoplasmic membranes) are rich in negatively-charged lipids (phosphatidylglycerol, cardiolipin, LPS, lipoteichoic acid). Mammalian cytoplasmic membranes carry a zwitterionic outer leaflet (phosphatidylcholine, sphingomyelin) and a high cholesterol content that stabilises the bilayer. The cationic face of LL-37 preferentially engages the negatively-charged microbial surface; the cholesterol-stabilised mammalian membrane is much less susceptible to insertion. Selectivity is concentration-dependent \u2014 at very high local concentrations LL-37 can become cytotoxic to mammalian cells as well.<\/p>\n
What is the “sword vs shield” model of LL-37 function?<\/h3>\n
The model describes the concentration-dependent functional switching of LL-37: at low concentrations (<5 \u00b5g\/mL) the peptide is dominantly immunomodulatory and tissue-protective \u2014 chemotactic, pro-angiogenic, LPS-neutralising. At high concentrations (>20 \u00b5g\/mL) the direct membrane-disruptive antimicrobial activity dominates. This dual nature underlies LL-37’s diverse roles in host defense and is one of the reasons careful dose-response characterisation is essential in any in-vitro or in-vivo research context.<\/p>\n
What is the link between LL-37 and psoriasis?<\/h3>\n
LL-37 is markedly overexpressed in psoriatic skin lesions and binds avidly to self-DNA and self-RNA released from damaged keratinocytes. These LL-37 \/ self-nucleic-acid complexes activate plasmacytoid dendritic cells via TLR9 (DNA) and TLR7 (RNA), driving the IFN-\u03b1-rich autoimmune-like inflammation that characterises psoriasis. Targeting the LL-37 \/ pDC \/ TLR axis is an active area of psoriasis pharmacology research.<\/p>\n
Why are some cancer studies pro-tumour while others are anti-tumour?<\/h3>\n
LL-37 has documented context-dependent effects on cancer. In some tumour types (ovarian, breast, lung, colorectal) elevated LL-37 expression correlates with worse outcome \u2014 likely through FPRL1-mediated pro-proliferative and pro-angiogenic signalling. In others (gastric, melanoma in some models) LL-37 has direct membrane-disruptive cytotoxic effect on tumour cells with weaker anti-tumour activity. The net effect depends on tumour type, local concentration, FPRL1 expression, and tumour-microenvironment composition.<\/p>\n
Why order research peptides from MedsBase:<\/strong> Lyophilized HPLC \u226599% peptides \u00b7 COA available on request \u00b7 Discreet temperature-stable packaging \u00b7 Worldwide peptide courier \u00b7 Reshipment Assurance<\/a> on every order \u00b7 1,400+ verified klantbeoordelingen<\/a><\/div>\n<\/p>","protected":false},"excerpt":{"rendered":"
\u2705 Only human cathelicidin antimicrobial peptide (37 aa)
\n\u2705 Amphipathic \u03b1-helix; +6 net charge
\n\u2705 Broad-spectrum: Gram+, Gram\u2212, enveloped viruses, biofilms
\n\u2705 Immunomodulatory via FPRL1 + LPS neutralisation
\n\u2705 Studied in antimicrobial-resistance, wound healing, psoriasis, oncology<\/p>\n
LL-37<\/strong> bevat synthetisch peptideverbinding.<\/p>","protected":false},"featured_media":71408,"comment_status":"open","ping_status":"closed","template":"","meta":[],"product_brand":[],"product_cat":[5426],"product_tag":[6465,6464,6463,5441],"class_list":{"0":"post-71392","1":"product","2":"type-product","3":"status-publish","4":"has-post-thumbnail","6":"product_cat-peptides","7":"product_tag-cap-18","8":"product_tag-cathelicidin","9":"product_tag-ll-37","10":"product_tag-peptide","12":"first","13":"instock","14":"shipping-taxable","15":"purchasable","16":"product-type-variable","17":"has-default-attributes"},"acf":[],"_links":{"self":[{"href":"https:\/\/medsbase.com\/nl\/wp-json\/wp\/v2\/product\/71392","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/medsbase.com\/nl\/wp-json\/wp\/v2\/product"}],"about":[{"href":"https:\/\/medsbase.com\/nl\/wp-json\/wp\/v2\/types\/product"}],"replies":[{"embeddable":true,"href":"https:\/\/medsbase.com\/nl\/wp-json\/wp\/v2\/comments?post=71392"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/medsbase.com\/nl\/wp-json\/wp\/v2\/media\/71408"}],"wp:attachment":[{"href":"https:\/\/medsbase.com\/nl\/wp-json\/wp\/v2\/media?parent=71392"}],"wp:term":[{"taxonomy":"product_brand","embeddable":true,"href":"https:\/\/medsbase.com\/nl\/wp-json\/wp\/v2\/product_brand?post=71392"},{"taxonomy":"product_cat","embeddable":true,"href":"https:\/\/medsbase.com\/nl\/wp-json\/wp\/v2\/product_cat?post=71392"},{"taxonomy":"product_tag","embeddable":true,"href":"https:\/\/medsbase.com\/nl\/wp-json\/wp\/v2\/product_tag?post=71392"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}