Urification strategy. The original cartridges have a capacity of up to 0.3 oles and are popular for the purification of oligonucleotides prepared on the 40 nmole and 0.2 ole scales. However, 1 ole syntheses have to be split among three of the original cartridges for optimal yield. Now, we are happy to introduce Poly-Pak II cartridges for the purification of oligonucleotides on a synthesis scale of up to 1 ole. (We will, of course, continue to offer the original Poly-Pak cartridges.) Using a Poly-Pak II cartridge, virtually all of the DMT-on product from a 1 ole synthesis is absorbed during the loading process. Poly-Pak Cartridges
Yields of up to 150 A260 units of a purified 20 mer can be expected. Poly-Pak II cartridges retain the same comfortable back pressure and low eluate volumes of the original Poly-Pak cartridges. Now you can purify an oligonucleotide synthesized on the 1 ole scale in good yield in less than 10 minutes.
Taditional radioactive labelling of oligonucleotides is being rapidly supplanted by non-isotopic procedures. Increased awareness of potential operator exposure to radiation, along with the increasing cost of proper disposal of radioactive waste, has clearly mandated some change. At the same time, diagnostic procedures using non-isotopically labelled oligonucleotides can be carried out in a much wider variety of testing laboratories. Currently, non-radioactive labelling is broken into two main segments: labelling using fluorescent tags which are detected directly at their emission wavelength; and labelling using tags like biotin or digoxigenin which are detected indirectly after capture or association with a suitably substituted enzyme or antibody.61849-14-7 medchemexpress Since the majority of oligonucleotides are destined for sequencing and amplification experiments, which require the 3′-terminus to be available for extension, labelling of the 5′-terminus is the most popular technique. While our future development of new labels will concentrate on 5′ labelling, it would be imprudent of us to neglect labelling of the 3′-terminus which can be especially useful in probe applications. However, the primary focus of this article is on a series of new 5′ labels, including fluorescent and nonfluorescent tags shown in Figure 1. FLUORESCEIN DYES Fluorescein labelled oligonucleotides have found applications in DNA sequencing and amplification, as well as techniques for genetic analysis. In the forefront of this development has been our current fluorescein phosphoramidite, Figure 1 (1), which has proved to be a popular, versatile and effective reagent for the preparation of labelled oligonucleotides.305834-79-1 medchemexpress Using this product or the related support (2), fluorescein molecules may
be placed anywhere within the sequence.PMID:30020674 Although the branched structure of the spacer allows a degree of versatility, it can cause some minor complications in use. Due to steric hindrance of the phosphoramidite, an increased coupling time of 15 minutes is optimal. Also, purified oligonucleotides labelled with this product exhibit multiple peaks, especially in reverse phase (RP) HPLC, even though the product is prepared from the 5-carboxyfluorescein isomer alone. (Fluorescein’s interesting numbering system is detailed in Figure 2.) This multiplicity is the result of diastereomer formation due to the chiral center in the spacer structure, along with the standard pH dependent structural variation of fluorescein as shown in Figure 2. A typical RP HPLC profile of an oligonucleotide labelled.MedChemExpress (MCE) offers a wide range of high-quality research chemicals and biochemicals (novel life-science reagents, reference compounds and natural compounds) for scientific use. We have professionally experienced and friendly staff to meet your needs. We are a competent and trustworthy partner for your research and scientific projects.Related websites: https://www.medchemexpress.com
