Portion mixing

One of these methods is the split-mix procedure, originally called portioning-mixing method, invented by Furka et al. [1-3]. This method was originally developed to enable the user to prepare millions of new peptides, but, later, was successfully used to synthesize organic libraries, too. The method is an embodiment of the combinatorial principle and the combinatorial thinking , which constitutes the theoretical background of the method and proved to be so fruitful in other areas, too. 

Sebestyen F, Dibo G, Furka A, Efficiency and limitations of the portioning-mixing peptide synthesis, In Schneider CH, Eberle AN eds., Peptides 1992, ESCOM, Leiden, 1993, p. 63. 

Meldal M, Svendsen I, Breddam K, Auzanneau FI, Portion-mixing peptide libraries of quenched fluorogenic substrates for complete subsite mapping of endoprotease specificity, Proc. Natl. Acad. Sci. USA, 91 3314-3318, 1994. 

A fundamental recipe for preparing combinatorial libraries is the randomization approach known as portion mixing. This technique is also called sptit-and-mix or divide-and-combine [4,5]. In this approach, solid-phase resins containing combinatorial library building blocks are portioned out, coupled, and combined to produce a combinatorial library of compounds. It is a way to synthesize a large... 

M. Meldal, I. Svendsen. Direct visualization of enzyme inhibitors using a portion mixing inhibitor library containing a quenched fluorogcnic peptide substrate. 1 Inhibitors for subtilisin Carlsberg. J. Chem. Soc., Perkin Trans. 1 1995, 1591-1596. 

Add 17.5 mL of diluted H2SO4 in three divided portions, mixing the acid and chocolate milk by a rotary motion after each dilution until digestion is completed. 

Acidify the bicarbonate solution (aqueous extract), still in the separatory funnel, with 6 mL of 1 M sulfuric acid. This step should be performed without delay, to avoid hydrolysis of the aspirin. The acid must be added slowly in small portions. Mix well only after most of the carbon dioxide evolution has ceased. The pH at this point should be 1 to 2 (pH test paper). Extract the acidified solution with eight separate 10-mL portions of methylene chloride and filter through a methylene chloride-wet paper into a 100-mL volumetric flask. Dilute to volume. Then, dilute further a 5-mL portion of this solution to 25 mL with methylene chloride in a volumetric flask. 

Figure 3 RP-HPLC analysis of two pools of four tripeptides prepared according to the portioning-mixing method. Peptide sequences are peak 1, YIH peak 2, YLH peak 3. YIR peak 4, YLR peak 5, VIH peak 6, VLH peak 7 VIR peak 8, VLR.

Figure 6 Amino acid composition of sublibraries having the general formula (Cys-02-X,-Asn)2-Lys-Gly, where O, denotes the known residue in the sublibrary and X, is the random residue, prepared according to the portioning-mixing method, where each sublibrary contains 18 distinct peptides.

In the northern part of Nigeria, sweet potato is processed into a local drink called kunuzaki. Fresh sweet potato is peeled, blended/grated or ground, sifted separated into boiled and unboiled portions, mixed, and left overnight to ferment and sugar added. 

Two distinct strategies of peptide lihrary preparation are commonly used parallel synthesis and so-called sptit-and-mix chemistry (also known as divide-couple- ecom-bine, portion-mixing and split-pool synthesis). Both are often described as combinatorial chemistry (combichem), although this is only strictly true for sptit-and-mix synthesis. Parallel synthesis is simply the preparation of many batches of peptide at the same time in separate parallel channels of one or more machines. In the case of library synthesis, the amino acid sequence is systematically varied between channels. Commonly this allows the synthesis of several hundred different sequences at the same time. It has the advantages that larger amounts are usually prepared than in split-and-mix, and that one can easily tell what sequence of residues was used in any potential hit. 

From filtrates of both the test and the control, pipette 0.5-ml portions, mix each sample with 2.5 ml of solution, and polarograph from —0.8 V at a suitable sensitivity (1/300). Measure the fference in mm between the respective wave heights of control and test. 

In the split-pool procedure, also known as the portioning-mixing method, the solid support is first divided into as many equal portions as the number of amino acids in the peptide s sequence [74,75,83], Each portion is coupled individually to only one amino acid. All portions of the resin are mixed, and the entire process of splitting and combining is repeated until all amino acids have been combined. An exorbitantly large number of derivatives can be synthesized at a time. 

Baltimore, MD, Memory Study participants (N = 964), cross-sectional portion, mixed gender, mixed ethnic older subjects Tibial Pb levels SBP, DBP, hypertension Nonsignificant association between tibial Pb and hypertension, no association of tibial Pb with BP Martin et al. (2006)... 

Split-and-pool (also referred to as split-and-mix, portioning-mixing, or split-and-recombine)... 

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