Protein printing methods

As mentioned before, the amount of soluble tannin that causes astringency in persimmon fruits is usually estimated visually by the tannin print method and can be measured quantitatively by the Folin-Denis method. There is also a protein precipitation method for the measurement of soluble tannins (Hagerman and Butler 1978). In that method, the soluble tannin content is assayed by the addition of the sample to a standard solution of protein and the isolation of insoluble tannin-protein complexes. The complexes are dissolved in alkaline solution, to which ferric chloride is added. The absorbance of the solution at 510 nm is measured. 

In this chapter, we will survey the kinds of solid supports (substrates) and surface chemistries currently used in the creation of nucleic acid and protein microarrays. Which are the best supports and methods of attachment for nucleic acids or proteins Does it make sense to use the same attachment chemistry or substrate format for these biomolecules In order to begin to understand these kinds of questions, it is important to briefly review how such biomolecules were attached in the past to other solid supports such as affinity chromatography media, membranes, and enzyme-linked immxm-osorbent assay (ELISA) microtiter plates. However, the microarray substrate does not share certain unique properties and metrics with its predecessors. Principal among these are printing, spot morphology, and image analysis they are the subjects of subsequent chapters. 

Daub, M., TopSpot Technology highly parallel dispensing for production of microarrays, Presentation 2002, Euro Biochips Conference, Berlin, Germany. Delehanty J.B. and Ligler, PS., Method for printing functional protein microarrays, Biotechniques 34, 380-385, 2003. 

New instrumentation for the analysis of the proteome has been developed including a MALDI hybrid quadrupole time of flight instrument which combines advantages of the mass finger printing and peptide sequencing methods for protein identification (Andersen and Mann 2000). 

The methods described below outline (1) the construction of the expression plasmids, (2) the induction of protein expression, (3) the extraction of the protein from E. coli, (4) the printing of a protein microarray, and (5) the assay of the protein microarray for DNA binding function. 

Fig. 7. Contact printing using solid pins provides a rapid, convenient method for fabrication of protein microarrays on many different surfaces.

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