Single purification

If the hGH is exported to the culture medium the product can easily be collected by removal of the cells from the culture medium by centrifiigation. Purification of hGH from the culture medium is faciUtated by low amounts of contaminating proteins present. In fact, it has been shown that hGH can be purified on a laboratory scale by a single purification step on a reversed-phase hplc column (43). Mammalian cells growing in tissue culture have also been used as hosts to produce hGH, which is exported into the culture media (44). 

Improvements in the abiUty to control operating conditions and in contractor designs have allowed a steady reduction in the number of purification steps required. The THORP faciUty, commissioned as of 1994 in the U.K., uses only a single purification step. 

After the second extraction/stripping cycle, the plutonium is concentrated by evaporation or by preferential adsorption (qv) on ion-exchange resins. As in the case for uranium, the newer faciHties, such as THORP, use only a single purification step. 

A clean-up process-scale RP-HPLC step has been introduced into production of human insulin prb. The C8 or C18 RP-HPLC column used displays an internal volume of 80 1 or more, and up to 1200 g of insulin may be loaded during a single purification run (Figure 11.4). Separation is achieved using an acidic (often acetic-acid-based) mobile phase (i.e. set at a pH value sufficiently below the insulin pi value of 5.3 in order to keep it fully in solution). The insulin is usually loaded in the water-rich acidic mobile phase, followed by gradient elution using acetonitrile (insulin typically elutes at 15-30 per cent acetonitrile). 

MCCs are an easy and reliable way to obtain medium-large solution libraries via the simultaneous reaction of more than two reagents in solution. Even a single randomization step, in fact, may produce a 10000-member library, using 4 monomer sets of 10 individuals, and only a single purification/ work-up procedure is required. 

PSA would be used as a front-end purifier for the synthesis of ammonia. The PSA system would produce, in a single purification step, an amnonia synthesis gas, free of the usual argon and methane inerts and, as a further advantage, would eliminate the need for the purge stream from the ammonia synthesis loop. 

Preussomerin I 697 and ( )-preussomerin G 698 were obtained from 620 with a five- and six-steps sequence in 15% and 12% overall yield, respectively, through modifications of substituents of the dioxocin ring. Thus, attack of lithium methoxide from the less hindered face of the enone 620, followed by protection of the phenolic oxygen as its methyl ether provided the methoxy adduct 692. The ketone 693 was obtained through a benzylic bromination-solvolysis-oxidation protocol, which required only a single purification. The C(2)-C(3) olefin was introduced by selective silylation of the C-l carbonyl of diketone 693 and oxidation of the silyl enol ether with Pd(OAc)2. Enone... 

Many proteins have been utilized as affinity ligands and there are literally thousands of references using this technique. The following are a few samples of proteins used as affinity ligands. Antibodies or antigens are used as immunoaffinity ligand to separate the complementary counterparts. Often, only a single purification step is needed because of the superior selectivity of... 

Having established the relative reactivity potential of the above donors and acceptors, the same group [107] then performed an efficient synthesis of oligosaccharides in a one-pot strategy through a single purification. The synthesis of tetra-... 

Fermentation is usually followed by the removal of cells from the culture broth, either by centrifugation or by filtration (Westoby et al., 2011). The cell-free broth is then concentrated by ultrafiltration, ammonium sulfate precipitation, or extraction with an organic solvent (Saxena et al., 2003). A single purification step is usually not adequate to get lipase of high purity. Therefore, purification using a combination of chromatographic techniques is mainly employed. However, except in the pharmaceutical industry, pure lipases are required and crude enzymes are usually adequate. 

Figure 1 Protein pattern of the single purification steps...

The synthesis of ABT-839 H2S04 was completed in eight chemical operations (10 steps total) in an overall yield of 43%. This synthesis was used to produce 4 kg of ABT-839 free amine and 2 kg of ABT-839 H2S04. The general approach was to utilize disconnections similar to those used in the original synthesis with an emphasis on streamlined work-up procedures and a single purification prior to final isolation. The steps for appending the two sidechains to... 

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