CheKine™ Micro Lysine Assay Kit: Your Top Questions Answered About the First Limiting Amino Acid

H3: What is lysine and why is it called the "first limiting amino acid"?

Lysine is one of the essential amino acids for the human body, promoting development, enhancing immune function, and improving the function of the central nervous system[reference:17]. It is a basic essential amino acid[reference:18]. However, because the lysine content in cereal foods is very low and it is easily destroyed and lost during processing, it is called the "first limiting amino acid"[reference:19]. This makes accurate lysine quantification essential for nutritional research, food science, and metabolic studies.

H3: What sample types are compatible with this kit?

The CheKine™ Micro Lysine (LYS) Assay Kit is compatible with a wide variety of biological samples, including serum, plasma, animal and plant tissues, cells, cell supernatants, and bacteria[reference:20]. This broad compatibility makes it a versatile tool for researchers across multiple disciplines.

H3: How does the lysine detection work?

The principle is elegantly simple: the lysine in protein has a free ε-NH2, which can react with ninhydrin hydrate to produce blue-purple substances[reference:21]. These substances have a maximum absorption peak at 570 nm[reference:22]. The lysine content of the sample is calculated by measuring the absorbance at 570 nm[reference:23].

H3: How sensitive is this assay?

The kit offers a broad linear range of 0.125–8 μmol/mL with a limit of detection of 0.03125 μmol/mL[reference:24]. This sensitivity enables accurate quantification even in low-abundance samples.

H3: What are the key features of this kit?

• Determination of lysine content in a variety of biological samples[reference:25]
• Broad linearity range: 0.125–8 μmol/mL[reference:26]
• Detailed sample preparation and result calculation methods are provided[reference:27]
• Standard and standard curve line are included for accurate quantification[reference:28]
• 12-month shelf life when stored at 4°C, protected from light[reference:29]

H3: Has this kit been validated in publications?

Yes. The kit has been cited in 2 publications[reference:30]:

• A study in Cellular and Molecular Life Sciences (IF: 6.2) on circ0066187 promoting pulmonary fibrogenesis through targeting STAT3-mediated metabolism signal pathway[reference:31]
• A study in Journal of Leukocyte Biology (IF: 3.6) on Djulis stems as a sustainable sawdust alternative for mushroom cultivation[reference:32]

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