9780521516358book.pdf

part to there being more bound mobile anions (or cations) than bound cations (anions) at this pH. This could mask an imbalance o ...

The progressive condensation of many molecules of amino acids gives rise to an unbranched polypeptide chain. By convention, the ...

linking different chains (inter-chain). An individual polypeptide chain in an oligo- meric protein is referred to as a subunit. ...

H 4 LDH1 H 3 M LDH2 H 2 M 2 LDH3 HM 3 LDH4 M 4 LDH5 Each isoenzyme promotes the same reaction but has different kinetic constant ...

in practice, on average, only four different fractionation steps are needed to purify a given protein. Indeed, in exceptional ci ...

since, as will be seen below, the development of colour is often at least partly dependent on the amino acid composition of the ...

in-line variable wavelength ultraviolet light detectors that monitor protein elution from columns. Lowry (Folin–Ciocalteau) meth ...

with concentrated sulphuric acid in the presence of sodium sulphate (to raise the boiling point) and a copper and/or selenium ca ...

Extraction buffer Normally extraction buffers are at an ionic strength (0.1–0.2 M) and pH (7.0–8.0) that is considered to be com ...

can then be removed by centrifugation. Thiol compounds (reducing agents) are also added to minimise the activity of phenol oxida ...

disrupting cells are described below. Which method one uses depends on the nature of the cell wall/membrane being disrupted. Mam ...

Cell disruption methods Blenders These are commercially available, although a typical domestic kitchen blender will suffice. Thi ...

Yeast can be similarly disrupted using enzymes to degrade the cell wall and either osmotic shock or mild physical force to disru ...

assay), such asb-galactosidase, then the presence of the protein of interest can be detected by the presence of the linkedb-gala ...

Example 2ENZYME FRACTIONATION Question A tissue homogenate was prepared from pig heart tissue as the first step in the preparati ...

centrifugation. Any fat floating on the surface can be removed by coarse filtration through glass wool or cheesecloth. However, ...

Table 8.3 Example of a protein purification schedule Fraction Volume(cm 3 ) Proteinconcentration(mg U cm ^3 ) Totalprotein(mg) ...

sulphate. Protamine sulphate is a mixture of small, highly basic (i.e. positively charged) proteins, whose natural role is to bi ...

proteins denature can be a very useful preliminary step. The temperature at which the protein being purified is denatured is fir ...

(reduces the dielectric constant) and at the same time water molecules are used up in hydrating the organic solvent molecules. W ...