Labeled nucleotides are produced in a wide variety of specific activity, radiolabel and formulation to assure the achievement of appropriate sensitivity, resolution and convenience in assays. Nucleotides are produced by multi-stage enzymatic synthesis from carrier-free processed isotopes, followed by HPLC purification. ³²P and ³⁵S-nucleotides are supplied as the triethylammonium salt.

 ³⁵S-amino acids are prepared by growing a microorganism in a medium in which the only available source of sulfur is radioactive. The ³⁵S is incorporated into the protein chain of the microorganism. After harvesting and hydrolysis, L-[³⁵S]methionine is purified by high performance liquid chromatography.

³²P and ³⁵S Nucleotides

Majority of ³²P and ³⁵S radionucleotides are supplied in aqueous solution at 10 mCi/ml (370 MBq/ml). The conventionally formulated nucleotides are supplied in 10 mM Tricine buffer (pH 7.8) and 5 mM DTT (³²P radionucleotides) or 10 mM DTT (³⁵S radionucleotides). The SteadyBlue^TM and SteadyClear^TM nucleotides are supplied in stabilized (and colored) aqueous solution. The stabilized forms have the same performance in any application as the conventionally formulated equivalents due to the unique composition, the inert blue dye and the low salt concentration. If the visualization is important use the SteadyBlue^TM series. The conventionally formulated or the SteadyClear^TM series is recommended if an inert dye can cause any trouble in your application.

³⁵S-Amino Acids

The in vitro translation grade ³⁵S-Methionine is supplied at 10 mCi/ml (370 MBq/ml), 15 mCi/ml (555 MBq/ml) or 50 mCi/ml (2000 MBq/ml) radioactive concentration in 10 mM Tricine buffer (pH 7.4) containing 10 mM 2-mercaptoethanol.

IsoLabel^TM is a mixture of amino acids and contains approximately 70 % L-[³⁵S]Methionine and 30 % L-[³⁵S]Cysteine. The mix is for in vitro protein labeling and supplied in a sterile aqueous solution containing 10 mM Tricine buffer pH 7.4 and 10 mM 2-mercaptoethanol at 15 mCi/ml (555 MBq/ml). Both ³⁵S-Methionine and IsoLabel^TM are also available in SteadyBlue^TM formulation, i.e. stabilized and colored form.