McMMAF - ≥98% , CAS No.863971-19-1

CAS: 863971-19-1 Cat. No.: M596644 Formula: C₄₉H₇₆N₆O₁₁ Molecular Weight: 925.2 EC Number: 809-632-9 PubChem CID: 56949327

GRADE & PURITY ≥98%

Synonyms

FT-0615072 | Q27285195 | SCHEMBL10220875 | AC-32507 | McMMAF | MC-MMAF | MCMMA-F | N-((2R,3R)-3-((2S)-1-((3R,4S,5S)-4-((N-(6-(2,5-dioxo-2,5-dihydro-1H-pyrrol-1- yl)hexanoyl)-N-methyl-L-valyl-L-valyl)methylamino)-3-methoxy-5- methylheptanoyl)pyrrolidin-2-y

Storage

Store at -20°C,Argon charged

Shipped In

Ice chest + Ice pads

Overview

MC-MMAF is a precursor of antibody drug conjugate. This compound uses a maleimidocaproyl (MC) spacer and uses MMAF which is a synthetic antineoplastic agent.

Specifications

Synonyms

FT-0615072 | Q27285195 | SCHEMBL10220875 | AC-32507 | McMMAF | MC-MMAF | MCMMA-F | N-((2R,3R)-3-((2S)-1-((3R,4S,5S)-4-((N-(6-(2,5-dioxo-2,5-dihydro-1H-pyrrol-1- yl)hexanoyl)-N-methyl-L-valyl-L-valyl)methylamino)-3-methoxy-5- methylheptanoyl)pyrrolidin-2-y

Specifications & Purity

≥98%

Storage

Store at -20°C,Argon charged

Shipped In

Ice chest + Ice pads

This product requires cold chain shipping. Ground and other economy services are not available.

Action Type

ACTIVATOR

Purity

≥98%

Names and Identifiers

• Canonical Smiles: CCC(C)C(C(CC(=O)N1CCCC1C(C(C)C(=O)NC(CC2=CC=CC=C2)C(=O)O)OC)OC)N(C)C(=O)C(C(C)C)NC(=O)C(C(C)C)N(C)C(=O)CCCCCN3C(=O)C=CC3=O
• IUPAC Name: (2S)-2-[[(2R,3R)-3-[(2S)-1-[(3R,4S,5S)-4-[[(2S)-2-[[(2S)-2-[6-(2,5-dioxopyrrol-1-yl)hexanoyl-methylamino]-3-methylbutanoyl]amino]-3-methylbutanoyl]-methylamino]-3-methoxy-5-methylheptanoyl]pyrrolidin-2-yl]-3-methoxy-2-methylpropanoyl]amino]-3-phenylpropanoic acid
• InChIKey: ORFNVPGICPYLJV-YTVPMEHESA-N
• INCHI: 1S/C49H76N6O11/c1-12-32(6)44(37(65-10)29-41(59)54-27-19-22-36(54)45(66-11)33(7)46(60)50-35(49(63)64)28-34-20-15-13-16-21-34)53(9)48(62)42(30(2)3)51-47(61)43(31(4)5)52(8)38(56)23-17-14-18-26-55-39(57)24-25-40(55)58/h13,15-16,20-21,24-25,30-33,35-37,42-45H,12,14,17-19,22-23,26-29H2,1-11H3,(H,50,60)(H,51,61)(H,63,64)/t32-,33+,35-,36-,37+,42-,43-,44-,45+/m0/s1
• Isomeric SMILES: CC[C@H](C)[C@@H]([C@@H](CC(=O)N1CCC[C@H]1[C@@H]([C@@H](C)C(=O)N[C@@H](CC2=CC=CC=C2)C(=O)O)OC)OC)N(C)C(=O)[C@H](C(C)C)NC(=O)[C@H](C(C)C)N(C)C(=O)CCCCCN3C(=O)C=CC3=O
• PubChem CID: 56949327
• Molecular Weight: 925.2

Taxonomic Classification

Taxonomy Tree

• Kingdom Organic compounds
  • Superclass Organic acids and derivatives
    • Class Peptidomimetics
      • Subclass Hybrid peptides

• Kingdom: Organic compounds
• Superclass: Organic acids and derivatives
• Class: Peptidomimetics
• Subclass: Hybrid peptides
• Intermediate Tree Nodes: Not available
• Direct Parent: Hybrid peptides
• Alternative Parents: Dipeptides Phenylalanine and derivatives Valine and derivatives N-acyl-L-alpha-amino acids Alpha amino acid amides Phenylpropanoic acids Amphetamines and derivatives N-acylpyrrolidines Maleimides N-substituted carboxylic acid imides N-acyl amines Tertiary carboxylic acid amides Pyrrolines Dicarboximides Secondary carboxylic acid amides Azacyclic compounds Carboxylic acids Dialkyl ethers Monocarboxylic acids and derivatives Organonitrogen compounds Organopnictogen compounds Organic oxides Carbonyl compounds Hydrocarbon derivatives
• Molecular Framework: Aromatic heteromonocyclic compounds
• Substituents: Hybrid peptide - Alpha-dipeptide - Phenylalanine or derivatives - N-acyl-alpha-amino acid - Valine or derivatives - N-acyl-alpha amino acid or derivatives - N-acyl-l-alpha-amino acid - Alpha-amino acid amide - 3-phenylpropanoic-acid - Alpha-amino acid or derivatives - Amphetamine or derivatives - N-acylpyrrolidine - Maleimide - N-acyl-amine - Monocyclic benzene moiety - Carboxylic acid imide, n-substituted - Fatty acyl - Fatty amide - Benzenoid - Dicarboximide - Pyrrolidine - Pyrroline - Tertiary carboxylic acid amide - Carboxylic acid imide - Carboxamide group - Secondary carboxylic acid amide - Carboxylic acid derivative - Azacycle - Carboxylic acid - Dialkyl ether - Organoheterocyclic compound - Ether - Monocarboxylic acid or derivatives - Organic oxygen compound - Organic nitrogen compound - Organopnictogen compound - Organic oxide - Carbonyl group - Organooxygen compound - Organonitrogen compound - Hydrocarbon derivative - Aromatic heteromonocyclic compound
• Description: This compound belongs to the class of organic compounds known as hybrid peptides. These are compounds containing at least two different types of amino acids (alpha, beta, gamma, delta) linked to each other through a peptide bond.
• External Descriptors: Not available

Data sources

1. Djoumbou Feunang Y, Eisner R, Knox C, Chepelev L, Hastings J, Owen G, Fahy E, Steinbeck C, Subramanian S, Bolton E, Greiner R, and Wishart DS. ClassyFire: Automated Chemical Classification With A Comprehensive, Computable Taxonomy. Journal of Cheminformatics, 2016, 8:61.

DOI: 10.1186/s13321-016-0174-y

Chemical and Physical Properties

• Molecular Weight: 925.200 g/mol
• XLogP3: 4.600
• Hydrogen Bond Donor Count: 3
• Hydrogen Bond Acceptor Count: 11
• Rotatable Bond Count: 27
• Exact Mass: 924.557 Da
• Monoisotopic Mass: 924.557 Da
• Topological Polar Surface Area: 212.000 Ų
• Heavy Atom Count: 66
• Formal Charge: 0
• Complexity: 1680.000
• Isotope Atom Count: 0
• Defined Atom Stereocenter Count: 9
• Undefined Atom Stereocenter Count: 0
• Defined Bond Stereocenter Count: 0
• Undefined Bond Stereocenter Count: 0
• The total count of all stereochemical bonds: 0
• Covalently-Bonded Unit Count: 1

Application Protocols

The following are general, non-item-specific example workflows to assist with planning. Adjust per your system and consult the SDS.

• Preparation of McMMAF stock solution:

  1. Equilibrate a sealed vial to room temperature under argon to minimize condensation.
  2. Add anhydrous DMSO to prepare a 10 mM stock (e.g., 1.0 mg in an appropriate volume based on exact MW from CoA). Vortex gently until fully dissolved.
  3. Aliquot into low-bind microtubes, blanket with argon, and store at −20 °C. Avoid repeated freeze–thaw.

• Protein thiol conjugation (example):

  1. Reduce protein disulfides with 5–10 mM TCEP for 30–60 min at room temperature; remove excess reductant by spin desalting into 50 mM phosphate, 150 mM NaCl, pH 6.8.
  2. Add McMMAF stock to achieve 2–8 equivalents per accessible thiol; keep total DMSO ≤10% v/v.
  3. Incubate 30–90 min at 20–25 °C. Monitor by HIC or LC–MS for conjugation progress and DAR/DPR.
  4. Quench residual maleimide with 5–10 mM cysteine for 10 min if appropriate. Desalt into storage buffer.

• Peptide/small-molecule thiol conjugation (example):

  • Mix thiol partner (1.0 eq) with McMMAF (1.2–1.5 eq) in 50% ACN/50% 50 mM phosphate, pH 6.8, at room temperature for 30–60 min. Analyze by LC–MS and purify by RP-HPLC.

• Analytical characterization:

  • Use RP-HPLC with UV at 214/254 nm; confirm mass by ESI–MS. For proteins, employ intact mass and HIC profiling.

Biological Roles

Biological insights below reflect literature understanding of auristatin-class payloads and are not item-specific specifications or claims for this SKU. McMMAF is used strictly for research use only.

• Mechanistic class (literature):

  • Auristatin analog of dolastatin-10 that binds to tubulin at or near the vinca site, inhibiting tubulin polymerization and disrupting microtubule dynamics during mitosis.
  • The MMAF variant carries a C-terminal phenylalanine acid, which reduces membrane permeability relative to MMAE; this can lessen bystander effects in mixed cell populations.

• Biochemical consequences:

  • Mitotic arrest at G2/M, triggering apoptotic cascades in sensitive cells in vitro.
  • Effects on cytoskeletal-dependent processes such as intracellular trafficking and cell morphology in model systems.

• Role of the maleimide linker:

  • Enables selective covalent attachment to cysteine-containing biomolecules, controlling payload localization and facilitating targeted delivery concepts in vitro.

• Cellular handling (contextual):

  • Conjugate internalization and payload release depend on linker design; the noncleavable mc tether typically requires catabolism of the carrier to liberate active species within lysosomes (literature concept). These details vary by construct and are not inherent to the small molecule alone.

• Cautions:

  • Extreme potency at low concentrations mandates stringent containment and exposure control during all biological experiments.

No therapeutic or diagnostic use is implied or permitted for this product.

Buffer Applications

This product is not a buffering reagent. It does not form classical buffer systems or serve as a pH stabilizer.

• Practical note: For bioconjugation, McMMAF is typically introduced into standard buffers (e.g., phosphate or HEPES) at pH 6.5–7.2 with limited organic cosolvent (DMSO or ACN). Select buffers that are amine-compatible and free of competing thiols.

For guidance on choosing buffers for conjugation workflows, see the Reaction Conditions and Application Protocols sections.

Green Alternatives

While McMMAF is a specialized bioconjugation reagent rather than a commodity solvent, greener practices can be applied to its handling and use.

• Solvent choices (greener options, literature/general):

  • Prefer acetonitrile or ethanol/water co-solvent systems over DMF/NMP where performance allows; however, DMSO remains a practical and relatively benign high-performance solvent for stock solutions.
  • Minimize DMF/NMP volumes due to reproductive toxicity concerns; validate DMSO or ACN alternatives for dissolution and conjugation delivery.

• Process intensification:

  • Use high-concentration DMSO stocks and micro-volume additions to reduce total solvent consumption.
  • Implement microdialysis or spin desalting instead of large-volume buffer exchanges.

• Waste reduction:

  • Plan reactions at the smallest scale compatible with analytical endpoints; auristatin potency allows picomole–nanomole studies, substantially lowering waste streams.
  • Segregate cytotoxic waste and ensure incineration per institutional policy.

• Comparison snapshot (informational):

  • DMSO: high solubility, low volatility, acceptable EHS profile; potential to transport into cells—use closed handling.
  • ACN: lower viscosity, easier removal; flammable and toxic—use in hood.
  • DMF/NMP: excellent solvents but higher worker exposure concerns; replace where feasible.

Note: No “green substitute” exists for the payload itself due to its specialized function; improvements center on solvent choice, scale minimization, and containment engineering.

Pharmaceutical Uses

No clinical or therapeutic use is indicated or permitted. For research use only.

• Research/manufacturing context (general):

  • McMMAF is commonly employed in preclinical process development for antibody–drug conjugates (ADCs) and related bioconjugates, enabling evaluation of conjugation strategies, DAR/DPR determination, stability studies, and analytical method development.
  • It may be used to establish in vitro functional assays (e.g., cytotoxicity on cell lines) for benchmarking conjugate potency and for studying linker stability.

• Excipient status:

  • Not used as an excipient; it is an active small-molecule payload intended for experimental conjugation chemistry.

• Pharmacopeial status:

  • Not specified for this item; refer to CoA/Spec Sheet. Auristatin payloads generally do not have compendial monographs given their specialized research application.

• Manufacturing considerations (developmental):

  • Payload handling follows high-potency API (HPAPI) containment practices: closed handling, dedicated equipment or isolators, and validated cleaning to control cross-contamination.
  • Analytical controls often include LC–MS identity/purity, maleimide integrity ratio, water/residual solvent content, and stability-indicating methods under ICH-like conditions, adapted for research scale.

Physical Properties

Item-specific physical properties were not provided in the Product Data. Do not treat the following as specifications; consult the item’s CoA/Spec Sheet for release criteria.

• Item-specific values:

  • Appearance: Not specified for this item; refer to CoA/Spec Sheet.
  • Molecular Weight: Not specified for this item; refer to CoA/Spec Sheet.
  • Molecular Formula: Not specified for this item; refer to CoA/Spec Sheet.

• General/literature-reported characteristics for mc–MMAF class materials (informational only):

  • Physical state: typically off-white to pale solid powders that are hygroscopic and light-sensitive.
  • Solubility: high in polar aprotic organic solvents (DMSO, DMF, NMP, acetonitrile); limited aqueous solubility unless formulated with co-solvent or converted to suitable salt forms. Aqueous buffer use generally requires ≤10–20% DMSO cosolvent or encapsulation.
  • UV characteristics: strong peptide bond absorbance near 210–220 nm; aromatic contributions near 254–280 nm (literature). Extinction coefficients are sequence- and solvent-dependent.
  • LogP/charge: MMAF-bearing payloads are less membrane permeable than MMAE analogs due to the C-terminal phenylalanine acid, imparting higher polarity/charge in neutral media (literature trend; exact values vary by salt state).
  • Thermal behavior: decompose before distillation; compounds are non-volatile solids. Differential scanning calorimetry often shows broad events rather than sharp melting points for peptide-like materials (literature observation).

Practical note: For accurate mass, elemental composition, water content, and chromatographic purity for this SKU, refer to the accompanying CoA/Spec Sheet.

Quality & Grades

• Grade/Purity for this specific SKU: Not specified for this item; refer to CoA/Spec Sheet. The Certificate of Analysis will define assay method (e.g., HPLC), purity threshold, and key attributes such as identity confirmation (HRMS/NMR) and residual solvents.

• What “research-grade auristatin linker–payload” typically implies (general guidance):

  • Identity confirmed by LC–MS/HRMS and often 1H NMR where feasible for peptide-like molecules.
  • Purity assessed by analytical reversed-phase HPLC with UV detection; some vendors also use ELSD or MS.
  • Counterion content (if present) and water content (Karl Fischer) may be reported; these significantly affect apparent MW and solubility.

• Stabilizer and formulation:

  • Stabilizers, if any, are not specified for this item; refer to CoA/Spec Sheet.
  • Maleimide-containing materials are commonly packaged under inert gas in amber vials to limit hydrolysis and radical oxidation.

• Practical QC considerations for mc–MMAF class materials (informational):

  • Monitor maleimide integrity (ratio of intact maleimide vs. ring-open hydrolyzed succinamic acid by LC–MS).
  • Track peptide-related impurities/epimers via gradient RP-HPLC; some epimerization can occur during synthesis or storage.
  • For bioconjugation applications, functional titer (thiol-reactivity) can be evaluated by reaction with a model cysteine reagent and subsequent LC–MS analysis.

Reaction & Applications

This compound is primarily used as a thiol-reactive linker–payload for constructing model ADCs and other bioconjugates.

• Core reactivity (literature/general):

  • Maleimide–thiol Michael addition: rapid, selective conjugation to cysteine residues on proteins/peptides in mildly acidic to neutral buffers, forming a stable thioether linkage.
  • Maleimide hydrolysis: competing pathway yielding ring-opened succinamic acid that is non-reactive toward thiols; minimized by pH 6.5–7.2, low temperature, and short exposure to aqueous media before use.

• Typical applications:

  • Preparation of cysteine-conjugated toxin–protein constructs for in vitro mechanism studies, payload potency benchmarking, and release-method evaluations.
  • Synthesis of small-molecule or peptide conjugates that deliver MMAF for cell-based studies.
  • Surface modification of thiol-bearing materials (e.g., nanoparticles) to generate toxin-decorated constructs for research.

• Practical tips:

  • Use freshly reduced proteins to generate reactive thiols; remove excess reductant (e.g., TCEP compatibility varies—TCEP can add to maleimides; consider partial desalting before adding McMMAF).
  • Maintain minimal headspace and inert gas overlay to limit oxidative degradation.
  • Quench unreacted maleimide with cysteine or mercaptoethanol after conjugation when appropriate.
  • Characterize conjugates by LC–MS (intact mass), UV/Vis, and hydrophobic interaction chromatography; determine drug-to-protein ratio (DPR) or drug-to-antibody ratio (DAR) where relevant.

• Expanded context:

  • MMAF payloads are valued for reduced bystander effects relative to MMAE due to lower membrane permeability (literature trend), informing selection in heterogeneous systems.

Reaction Conditions

The following conditions reflect general literature practices for maleimide–thiol conjugation with mc–MMAF-like reagents and are not item-specific specifications.

• Protein/peptide conjugation (thiol–maleimide Michael addition):

  • Buffer: phosphate or HEPES, pH 6.5–7.2; avoid Tris and other primary amines at high concentrations during coupling.
  • Reducing agents: generate free thiols with TCEP or DTT, then remove excess reductant (spin desalting or dialysis) before adding McMMAF to prevent maleimide consumption.
  • Solvent: deliver McMMAF from anhydrous DMSO at 5–10 mM. Keep final organic ≤10% v/v.
  • Temperature/time: 20–25 °C for 30–120 min; monitor progress by UV/HIC/LC–MS. Work at 4–8 °C if hydrolysis is problematic.
  • Stoichiometry: 2–10 eq per thiol for proteins; 1.1–2.0 eq for small peptides, adjusting to achieve target loading.

• Small-molecule thiol conjugation:

  • Solvent: ACN, DMSO, or mixed aqueous buffer at pH 6.8–7.0.
  • Base: none or minimal; excess base accelerates hydrolysis and can cause side reactions.

• Workup and purification:

  • Quench unreacted maleimide with cysteine or β-mercaptoethanol if needed.
  • Purify protein conjugates by desalting, size-exclusion, or HIC; small molecules by RP-HPLC.

• Stability notes:

  • Maleimide ring opening (hydrolysis) competes over time in water; minimize aqueous pre-incubation of McMMAF and use immediately after dilution.
  • Store intermediate solutions on ice and under argon; avoid repeated freeze–thaw of stock solutions.

Safety & Handling

Safety information specific to this item (GHS, H-statements, pictograms) is not provided in the Product Data. Always consult the SDS for authoritative guidance.

• Item-specific data from Product Data:

  • GHS Classification: Not specified for this item; refer to SDS.
  • Signal Word / H-Statements / Pictograms: Not specified for this item; refer to SDS.
  • Storage Conditions: Store at −20 °C, Argon charged.
  • Shipping: Ice chest + ice pads.

• General hazard profile for auristatin payloads (literature, informational only):

  • Potent cytotoxic/antimitotic agents that inhibit tubulin polymerization. Handle as highly hazardous at microgram levels.
  • Possible routes: inhalation, ingestion, skin/eye absorption; may cause reproductive toxicity and organ effects based on class behavior.

• Engineering controls and PPE (best practice for this class):

  • Work in a certified chemical fume hood or containment isolator.
  • Use double nitrile gloves, lab coat, eye protection; consider sleeve covers and respiratory protection per risk assessment.
  • Employ closed-transfer tools (low-retention tips, sealed vials), spill pads, and cytotoxic waste containers.

• Incompatibilities and stability:

  • Maleimides undergo hydrolysis and thiol-Michael addition; minimize exposure to nucleophiles (amines, thiols) and basic media.
  • Protect from moisture, light, and prolonged elevated temperature. Maintain inert atmosphere (argon) as specified.

• First-aid overview (consult SDS):

  • Skin/eyes: immediate decontamination with copious water; remove contaminated clothing.
  • Inhalation: move to fresh air; seek medical attention.
  • Ingestion/needlestick: seek urgent medical evaluation. Provide SDS to responders.

Solvent Selection

McMMAF is a polar, peptide-like small molecule with a hydrophobic surface punctuated by multiple amide functions and a maleimide electrophile. Solvent choice is driven by the need to dissolve at conjugation-relevant concentrations while preserving maleimide integrity.

• Polarity and miscibility (literature/general):

  • Highly soluble: DMSO, DMF, NMP, acetonitrile.
  • Moderately soluble: methanol, ethanol, isopropanol (risk of transesterification is low but hydrolysis can occur in alcoholic/basic media over time).
  • Aqueous buffers: limited solubility without cosolvent; up to 5–20% DMSO or ACN is commonly used to seed dissolution before dilution into buffer.

• Practical solvent selection tips:

  • Stock solutions: prepare 1–10 mM in anhydrous DMSO under argon, aliquot, and store at −20 °C.
  • For protein conjugation: deliver in minimal DMSO (≤10% v/v final) to buffered aqueous solution at pH 6.5–7.2 to favor thiol-Michael addition and limit maleimide hydrolysis.
  • Avoid prolonged exposure in basic buffers (pH >7.5), which accelerates maleimide ring opening, and avoid amine-rich solvents (e.g., neat TEA) prior to conjugation.

• Comparison (general):

  • DMSO vs ACN: DMSO offers higher solubility and ease of handling; ACN provides lower viscosity and faster mixing in aqueous buffers but may precipitate upon dilution if water fraction is high.
  • DMF/NMP: excellent solvents for small-molecule operations; for bioconjugation to proteins, limit to small percentages to preserve protein structure.

Storage & Reconstitution

• Item-specific storage from Product Data:

  • Store at −20 °C, Argon charged.
  • Shipped in an ice chest with ice pads.

• General best practices for mc–MMAF class materials:

  • Protect from light and moisture. Keep vials tightly closed with an inert gas headspace (argon) to limit hydrolysis and oxidation of the maleimide.
  • If provided as a solid, allow the sealed vial to reach room temperature before opening to avoid water condensation. Reseal promptly after use.

• Reconstitution guidance (non-specification):

  • Dissolve in anhydrous DMSO to prepare a concentrated stock (e.g., 5–10 mM, calculating exact volumes using the MW from the CoA/Spec Sheet). Mix gently until fully dissolved.
  • Filter through a 0.22 µm PTFE syringe filter if particulates are observed.
  • Aliquot into single-use portions in low-bind tubes, blanket with argon, label with concentration and date, and store at −20 °C.

• Stability of solutions (general):

  • DMSO stocks are typically stable for weeks to a few months at −20 °C when protected from moisture and oxygen; verify integrity by LC–MS prior to critical experiments.
  • Avoid repeated freeze–thaw; thaw an aliquot once, use immediately, and discard any remainder.

For exact shelf-life, assay, and any stabilizers or counterions specific to this SKU, consult the CoA/Spec Sheet.

Structure & Identity

McMMAF is widely recognized in the ADC (antibody–drug conjugate) field as a thiol-reactive auristatin linker–payload incorporating a maleimidocaproyl (mc) handle attached to the cytotoxic monomethyl auristatin F (MMAF) scaffold.

• Item-specific identifiers (from Product Data):

  • SKU: M596644
  • Product Name: McMMAF
  • CAS: 863971-19-1
  • CID: 56949327
  • InChIKey: 265279 (as provided)
  • SMILES: Not specified for this item; refer to CoA/Spec Sheet.
  • Molecular Formula: Not specified for this item; refer to CoA/Spec Sheet.
  • Molecular Weight: Not specified for this item; refer to CoA/Spec Sheet.

• Structural features (general/literature description, not item-specific):

  • Auristatin peptide analog composed of modified amino acid residues related to dolastatin-10 lineage; contains secondary and tertiary amides, a C-terminal phenylalanine motif (in MMAF), and lipophilic side chains.
  • The “mc” moiety is a maleimide fused five-membered imide ring tethered via a 6-atom aliphatic spacer (caproyl), providing a soft Michael acceptor for selective cysteine thiol conjugation.
  • Overall architecture: maleimide–(CH2)5–CO–(amide)–MMAF core. The maleimide double bond enables rapid 1,4-addition with thiols; the peptide region confers tubulin-binding cytotoxicity after release or retention, depending on conjugation design.

• 2D structural description (literature):

  • Left terminus: maleimide ring (electron-poor C=C) attached to a linear hexanoyl linker terminating in an amide.
  • Central: series of amide bonds forming the auristatin backbone with N-methylated residues and a valine-derived unit.
  • Right terminus: phenylalanine-derived aromatic ring and terminal carboxylate (in free acid forms of MMAF). No stereochemical details are specified here; auristatins typically possess multiple defined stereocenters.

Synthetic Utility

From a synthetic and bioconjugation standpoint, McMMAF offers a pre-installed thiol-reactive handle on a potent auristatin scaffold.

• Functional groups and reactivity (literature/general):

  • Maleimide: soft Michael acceptor for rapid 1,4-addition with thiols; susceptible to base-catalyzed hydrolysis to non-reactive succinamic acid.
  • Multiple amide bonds: confer stability; minimal nucleophilicity; good chromatographic behavior under RP-HPLC.
  • Aromatic residue (Phe) and hydrophobic segments: facilitate HIC and RP-HPLC separation of conjugates by hydrophobicity differences.

• Uses in synthesis:

  • Conjugation to cysteine-containing peptides/proteins to prepare reference standards for ADC characterization.
  • Attachment to thiol-terminated polymers, dendrimers, or nanoparticles to build multivalent toxin constructs.
  • Model studies of linker stability (maleimide vs ring-opened forms) and optimization of conjugation site chemistry.

• Retrosynthetic considerations:

  • The mc unit is typically installed late-stage via amide coupling onto MMAF; protecting-group strategy ensures maleimide survival.
  • Purification by preparative RP-HPLC is standard; careful drying avoids residual water that can hydrolyze maleimide.

• Analytical toolkit:

  • Monitor reactions by LC–MS; track exact mass of intact payload and of ring-open hydrolysate (+18 Da relative to maleimide form).
  • Use 1H NMR/2D NMR sparingly due to complexity; LC–MS and UV are primary QC methods.

Target Specificity

Not applicable. This product is a small-molecule linker–payload and does not have antigen/epitope or species specificity. For target engagement and biological effects, see the Biological Roles section.