Frequently Asked Questions （：Quesation ：Answer）
Are there any cautions for the label?
The label should contain free primary amines or N-terminal, and the sample should not contain Tris, glycerin, and reagents with amino.
Could this biotin labeling kit be used for labeling other proteins in addition to antibodies?
The principle of biotin labeling kit is the formation of stable amide bond between activated Biotin and amino of label. In addition, N-terminal of protein can be labeled. Protein contains primary amines, such as lysine, can be labeled.
When labeling protein with this kit, does the reaction ratio is the same proportion of 20:1 as labeling antibodies?
The molecular weight and lysine amount of protein should be considered. In general, it is recommended to label according to the concentration of 2 mg/mL. If the amount of lysine is about 10~15, the reaction ration can be 1:20. The proportion will be increased if the amount of lysine is more.
Can this kit be used for small or trace labeling?
The assay procedure in the manual is used for labeling 0.1~2 mg antibody. If you need to mark a smaller amount, we have a special trace labeling method used to label 20-100 μg antibody and the reaction system is 100 μL. (So the amount of Biotin should be increased if the labeling concentration is less than 2 mg/mL.)
How to detect the labeling efficiency?
The labeling kits on sale have their optimized labeling method. The labeling efficiency of these kits are generally above 90% from our test. In addition, antibodies in our ELISA kits are also labeled with Biotin labeling kit. The biotin labeling efficiency can be determined by detecting the biotin amount with our Biotin Detection Kit.
Can the Filtration tube in this kit be repeatedly used?
The Filtration tube in this kit can be repeatedly used no more than 3 times, but must be washed after the assay finished use the following method: Add purified water and gently pipetting for several times. Then add 0.2M NaOH, incubate for 10 minutes and centrifuge. Wash the tubes with purified water. The tube can put in the water for short term storage, while it should be preserved in 20% ethanol for long term storage. The used tubes should avoid of dry and keep moist.
How long is the shelf life of the activated biotin after dissolution?
The unopened freeze-dried biotin powder can be stored stably for 1 year at 4 ℃, and it can be stored for 4 weeks in the dark if sealed properly after opening/dissolving..
Is the protein with a molecular weight of 3.8 kD suitable to be operated with a 3 kD Filtration tube?
No. If your target protein has a molecular weight of 3.8 kD, you have to choose the Filtration tube with a blocked diameter of less than 3.8/3, otherwise there is possibility of skip or plugging aperture.
If my target protein has 43 lysine, but I just want to label less than 5 biotin molecules. Is it necessary to take quality control labeling? Are there any methods to verify the labeling effect and amount?
Considering the spatial configuration, the reaction ratio optimized by Elabscience is 1:20, so that 1 antibody will be labeled with 3~6 Biotin molecules. If you want to control the labeling amount to be less than 5, you should control the molar ration and take pre-experiment, and estimate the labeling amount with Our Biotin Detetcion Kit.
How to judge whether some specific substance (e.g., folic acid) can be labeled with FITC or not?
The target substance can be labeled if it contains free amine, and the amount of primary amine (lysine) should be considered for proteins. Small molecules can be determined according to the amino number. The containing nitrogen heterocyclic ring of folic acid contains 1 amine, so it can be labeled with FITC theoretically. But the amine on this site has a weak nucleophilicity, the labeling effect may not good and it should be judged according to the purpose of their experiment by customers.