Name: iFluor® 555 maleimide
Brand: AAT Bioquest
SKU: 1063
Price: 237 USD
Availability: InStock

iFluor® 555 maleimide

iFluor® 555 Maleimide is an orange-fluorescent, thiol-reactive dye for selective covalent labeling of antibodies, proteins, and other thiol-containing biomolecules in fluorescence-based research applications.

Thiol-Reactive Functionality: Maleimide group selectively reacts with free thiols, including cysteine residues.
Spectral Properties: Excitation at 557 nm and emission at 570 nm.
pH Sensitivity: iFluor® 555 fluorescence remains stable across pH 3–11.
Applications: Suitable for fluorescent conjugation of reduced antibodies and other thiol-containing proteins.

<p>HeLa cells were stained with mouse anti-tubulin followed with iFluor<sup>TM</sup> 555 goat anti-mouse IgG (H+L) (red); actin filaments were stained with Phalloidin-iFluor<sup>TM</sup> 488 conjugate (green); and nuclei were stained with DAPI (blue).</p>

Protocol

SDS

Catalog	Size	Price	Quantity
1063	1 mg	Price

Overview

AAT Bioquest's iFluor® dyes are optimized for labeling proteins, particularly antibodies. These dyes are bright, photostable, and have minimal quenching on proteins. They can be well excited by the major laser lines of fluorescence instruments (e.g., 350, 405, 488, 555, and 633 nm). iFluor® 555 dyes have fluorescence excitation and emission maxima of ~557 nm and ~570 nm respectively. The iFluor® 555 family has spectral properties essentially identical to those of Cy3® (Cy3® is the trademark of GE Healthcare). Compared to Cy3 probes, the iFluor® 555 family has much stronger fluorescence and higher photostability. Their fluorescence is pH-independent from pH 3 to 11. These spectral characteristics make this new dye family a superior alternative to Cy3®. iFluor® 555 family has become an excellent replacement for Cy3® and Alexa Fluor® 555 labeling dye (Cy3® and Alexa Fluor® are the trademarks of Invitrogen and GE Health Care). iFluor® 555 maleimide is reasonably stable and shows good reactivity and selectivity with the thiol group.

Calculators

Common stock solution preparation

Table 1. Volume of DMSO needed to reconstitute specific mass of iFluor® 555 maleimide to given concentration. Note that volume is only for preparing stock solution. Refer to sample experimental protocol for appropriate experimental/physiological buffers.

	0.1 mg	0.5 mg	1 mg	5 mg	10 mg
1 mM	105.493 µL	527.465 µL	1.055 mL	5.275 mL	10.549 mL
5 mM	21.099 µL	105.493 µL	210.986 µL	1.055 mL	2.11 mL
10 mM	10.549 µL	52.747 µL	105.493 µL	527.465 µL	1.055 mL

Molarity calculator

Enter any two values (mass, volume, concentration) to calculate the third.

Mass (Calculate)		Molecular weight		Volume (Calculate)		Concentration (Calculate)		Moles
mg	÷	947.93 g/mol	=	mL	x	mM	=	mmol

Citations

View all 10 citations: Citation Explorer

Intranasal Drop of Multiplex RNA Therapy for SARS-CoV-2 Infections: Baicalein-Enhanced FEN1 Nuclease Cleaving as a Virus Buster

Authors:

Cao, Jiyanuo and Wan, Meng and Gu, Jiayu and Wang, Peiliang and Gao, Yuan and Wei, Libin and Guo, Yongjian and Zhao, Lingzhi and Xu, Shu

Journal:

Emerging Microbes \& Infections (2026): 2706349

Structural mechanism of biased activation of T cell receptor by a high-affinity antibody

Authors:

Li, Xiang and Huang, Buliao and Shao, Enze and Zhu, Yuwei and Yang, Dehui and Chen, Yan and Gao, Wenbo and Lu, Zebin and Lu, Fengliang and Zhang, Anqi and others,

Journal:

Vita (2026)

Three-dimensional printed PCL/nHA scaffolds promote soft tissue functional fibrosis to repair chest wall defect via Piezo1/Ca2+ signal during respiratory motion

Authors:

Zhang, Yuanquan and Li, Xing and Meng, Zijie and Ma, Minghai and Huang, Rou and Liang, Xiao and Liu, Sida and Wei, Wenyuan and Huo, Yangfan and Li, Yizhang and others,

Journal:

Bioactive Materials (2026): 846--861

Membrane fission during bacterial spore development requires cellular inflation driven by DNA translocation

Authors:

Landajuela, Ane and Braun, Martha and Mart{\'\i}nez-Calvo, Alejandro and Rodrigues, Christopher DA and Perez, Carolina Gomis and Doan, Thierry and Rudner, David Z and Wingreen, Ned S and Karatekin, Erdem

Journal:

Current Biology (2022): 4186--4200

A new FRET-based platform to track substrate ubiquitination by fluorescence

Authors:

Wu, Kenneth and Ching, Kevin and Chong, Robert A and Pan, Zhen-Qiang

Journal:

Journal of Biological Chemistry (2021)

References

View all 49 references: Citation Explorer

Simultaneous detection of virulence factors from a colony in diarrheagenic Escherichia coli by a multiplex PCR assay with Alexa Fluor-labeled primers

Authors:

Kuwayama M, Shigemoto N, Oohara S, Tanizawa Y, Yamada H, Takeda Y, Matsuo T, Fukuda S.

Journal:

J Microbiol Methods (2011): 119

Neuroanatomical basis of clinical joint application of "Jinggu" (BL 64, a source-acupoint) and "Dazhong" (KI 4, a Luo-acupoint) in the rat: a double-labeling study of cholera toxin subunit B conjugated with Alexa Fluor 488 and 594

Authors:

Cui JJ, Zhu XL, Ji CF, Jing XH, Bai WZ.

Journal:

Zhen Ci Yan Jiu (2011): 262

Fluorescent "Turn-on" system utilizing a quencher-conjugated peptide for specific protein labeling of living cells

Authors:

Arai S, Yoon SI, Murata A, Takabayashi M, Wu X, Lu Y, Takeoka S, Ozaki M.

Journal:

Biochem Biophys Res Commun (2011): 211

Sequential ordering among multicolor fluorophores for protein labeling facility via aggregation-elimination based beta-lactam probes

Authors:

Sadhu KK, Mizukami S, Watanabe S, Kikuchi K.

Journal:

Mol Biosyst (2011): 1766

Visualizing dengue virus through Alexa Fluor labeling

Authors:

Zhang S, Tan HC, Ooi EE.

Journal:

J Vis Exp. (2011)

Physical properties

Molecular weight	947.93
Solvent	DMSO

Spectral properties

Correction factor (260 nm)	0.23
Correction factor (280 nm)	0.14
Extinction coefficient (cm ^-1 M ^-1)	100000 ¹
Excitation (nm)	557
Emission (nm)	570
Quantum yield	0.64 ¹

Usage and storage

Intended use	Research Use Only (RUO)
Storage	Freeze (< -15 °C); Minimize light exposure

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Page updated on October 31, 2026