Nucleic acid derivatives general

Another important application of this interaction is in the formation of self-assembled bilayers on silver or gold surfaces. Ebersole et al. [457] showed that avidin and streptavidin molecules will adsorb onto clean layers of Au or Ag from an aqueous solution. Such layers can then be employed to capture biotinylated compounds. These authors used this technique to attach fragments of nucleic acid derived from the herpes virus to a solid support. A more popular approach to this general problem has, however, been to start by adsorption of a suitable biotin... 

The hybridisation properties of various 6-membered nucleic acid derivatives with complementary RNA have been studied. The 6-membered nucleic acid derivatives studied are a- or P-hexitol nucleic acid, HNA, cyclohexene nucleic acid, CeNA, (55), cyclohexane nucleic acid, CNA, and a- or p-homo-DNA, (56-58). Considerable cross-pairing of the nucleic acid derivatives was observed, and apart from p-homo-DNA, all analogues bound to RNA with generally greater stability than RNA RNA in a polyAipolyT duplex. The most stable duplex was p-HNA p HNA. 

Generally used when ion exchange properties are not needed. Most often used for the separation of sugars, amino acids, and similar compounds. A popular sorbent for the separation of nucleic acid derivatives, it separates pyrimidines (faster /7ys) from purines. Commercial grade microcrystalline cellulose (Avicel) has been used for the retention of guanine (base or nucleoside) in either acid (HCI formic acid) or base (ammonia) solvents. 

Zoller, M. J., and Smith, M., Oligonucleotide-Directed Mutagenesis Using M13-Derived Vectors an Efficient and General Procedure for the Production of Point Mutations in Any Fragment of DNA. Nucleic Acids Res., 1982. 10(20) pp. 6487-6500. 

Thiamine shows a pH-dependent UV absorbance range of 230-270 nm. However, its UV absorbance is prone to interference by other endogenous UV absorbers in foods, such as nucleic acids (67,68). In a recent interlaboratory comparison of thiamine methods (42), the results obtained from an HPLC method using UV absorbance detection were rejected due to the presence of peaks that interfered with thiamine. In the interests of increased sensitivity and selectivity, the thiamine vitamers are generally converted to their thiochrome derivatives by alkaline oxidation and determined fluorimetrically (42,70). The thiochrome derivatives of thiamine and its phosphate esters all fluoresce at nearly identical excitation (365-375 nm) and emission (425-435 nm) maxima at pH over 8. The thiochrome derivatives are all relatively stable in alkaline solution at pH greater than 9 and room temperature. 

The test depends on the 2-desoxyribose component of the nucleic acid and in experiments directed towards the synthesis of this sugar and its derivatives, the diphenylamine reaction has been used to obtain indications of the formation of the required product. Originally it was claimed that the test was specific for 2-desoxyribose but more recent investigations by Stacey and his coworkers48 have shown that the test is given by 2-desoxypentoses generally. Moreover, these workers have elucidated in part the mechanism of the test.48 These studies will be discussed more fully subsequently. 

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