WARNING: This product is for research use only, not for human or veterinary use.

MedKoo CAT#: 620107

CAS#: 1286754-10-6 (acid)

Description: Maleimide-PEG4-NHS, also known as Mal-PEG4-NHS, is a sulfhydryl and amine reactive heterofuncational PEG linker. The chemical bonds formed through Maleimide-PEG4-NHS linker are stable and are not cleavable. The NHS ester reacts with amino groups at pH 7-9 to form stable amide bond while maleimide reacts with thiol groups at pH 6.5-7.5 to form stable thiol-ether bond. Maleimide-PEG4-NHS is a useful linker for various biomolecule crosslinking applications (such as to make antibody drug conjugates (ADCs).

Price and Availability




Maleimide-PEG4-NHS is not in stock, but may be available through custom synthesis. For cost-effective reason, minimum 1 gram order is requested. The product will be characterized by NMR, HPLC and MS analysis. Purity (HPLC) is usually >98%. CoA, QC data, MSDS will be provided when product is successfully made. The estimated lead time is 2-3 months. Please send email to to inquire quote.

Chemical Structure


Theoretical Analysis

MedKoo Cat#: 620107
Name: Maleimide-PEG4-NHS
CAS#: 1286754-10-6 (acid)
Chemical Formula: C18H24N2O10
Exact Mass: 428.1431
Molecular Weight: 428.394
Elemental Analysis: C, 50.47; H, 5.65; N, 6.54; O, 37.35

Synonym: Maleimide-PEG4-NHS; MAL-PEG4-NHS; Maleimide PEG NHS; MAL-PEG-NHS; Maleimido-​Tetra(Ethylene Glycol)​-​Acetic Acid NHS ester.

IUPAC/Chemical Name: 2,5-dioxopyrrolidin-1-yl 14-(2,5-dioxo-2,5-dihydro-1H-pyrrol-1-yl)-3,6,9,12-tetraoxatetradecanoate


Technical Data

Solid powder

>98% (or refer to the Certificate of Analysis)

Shipping Condition:
Shipped under ambient temperature as non-hazardous chemical. This product is stable enough for a few weeks during ordinary shipping and time spent in Customs.

Storage Condition:
Dry, dark and at 0 - 4 C for short term (days to weeks) or -20 C for long term (months to years).

Soluble in DMSO

Shelf Life:
>2 years if stored properly

Drug Formulation:
This drug may be formulated in DMSO

Stock Solution Storage:
0 - 4 C for short term (days to weeks), or -20 C for long term (months).

Harmonized System Code: