Zinc constitutes more than 200 metalloenzymes and is an element involved in the synthesis of nucleic acids and proteins.

Zinc is particularly essential for cell replication in mammals and acute zinc deficiency during growth has been reported to cause skin, hair disorders and growth retardation. Therefore, an adequate supply of zinc is important for healthy physical development. Zinc is a trace element that has been the focus of increasing attention in medical and nutritional research in recent years.

This method determines zinc concentration by observing the color change in the visible region by the formation of a chelate complex between 5-Br-PAPS and zinc.

Zinc coordinated to proteins and low-molecular metabolites is dissociated by a denaturant in the reagent, and then coordinated to 5Br-PAPS to form a zinc chelate complex. This zinc chelate complex has an absorption maximum at a wavelength of around 560 nm, and the zinc concentration can be determined by measuring the absorbance.

◯ Samples that can be directly quantified with this kit

Examples: serum, plasma, urine

The denaturant in the kit dissociates zinc from the protein and develops color. No specific pretreatment is required.

※ Do not use blood collection tubes containing EDTA which may affect the assay value.

※ When using urine samples, preserve it by adding HCl and adjust the pH to 2~3 when measuring.

◯ Samples that require acid extraction

Examples: cell lysates, tissue homogenates, and other aqueous solution samples

The pH of the samples was adjusted to low level to dissociates the zinc from the protein, and the supernatant was used as the assay sample. However, only the following chemicals can be measured.

・Free zinc

・Protein-bound (coordinated) zinc (Protein-Zn2+, e.g. albumin, metallothionein)

・Other coordination-bound zinc

※ Do not use lysis buffers containing EDTA as they may affect the measured values.

※ Acid digestion should be performed in the case of organic zinc and heme-zinc.

◯ Samples that require microwave method and organic matter mixed acid decomposition

Example: Samples containing strong chelating agents such as EDTA, organic zinc (-C-Zn-C- single bonded), zinc encapsulated in a cyclic ligand (Zn-porphyrin, etc.)

Acid extraction is necessary when measuring chemical species that cannot be dissociated or samples containing interfering substances such as strong zinc chelating agents.

※ After decomposition of organic matter, adjust the pH to 2-3, and use the sample as the assay sample.

(1) ) Add 12 µl of DIW, standard solution, and assay sample to wells of a 96-well plate.

(2) Apply 230 µl of RA solution to each well.

(3) Incubate the plate at room temperature for 5 minutes.

(4) Measure absorbance at main wavelength 560 nm (secondary wavelength 700 nm.)

(5) ) Calculate the zinc concentration using the following formula:

(1) Measurement of zinc concentration in control serums using this kit

Figure 1: Results of measurement of control serum with known zinc concentration.

(2) Dilution linearity

Figure 2: Dilution linearity of standard sample

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