What do you mean by instability index?

The instability index provides an estimate of the stability of your protein in a test tube. Statistical analysis of 12 unstable and 32 stable proteins has revealed [7] that there are certain dipeptides, the occurence of which is significantly different in the unstable proteins compared with those in the stable ones.

What do you mean by instability index of a protein?

The instability index is an estimation of the stability of a protein experimentally. A protein whose instability index is smaller than 40 is predicted as stable [19]. The instability index values for our hypothetical and conserved proteins range from 18.43 to 45.31.

How is gravy score calculated?

The GRAVY value is calculated by adding the hydropathy value for each residue and dividing by the length of the sequence (Kyte and Doolittle; 1982).

What is pI in bioinformatics?

The isoelectric point (pI, pH(I), IEP), is the pH at which a molecule carries no net electrical charge or is electrically neutral in the statistical mean. The standard nomenclature to represent the isoelectric point is pH(I).

What does the GRAVY value tell you?

GRAVY (Grand Average of Hydropathy): GRAVY score can be calculated as the sum of the hydropathy values for all the amino acids in a protein divided by the total number of residues in it. Negative GRAVY value indicates that the protein is non-polar and positive value indicates that the protein is polar.

Why isoelectric point is important?

The isoelectric point is significant in protein purification because it represents the pH where solubility is typically minimal. Here, the protein isoelectric point signifies where mobility in an electro-focusing system is zero—and, in turn, the point where the protein will collect.

What happens when pH is less than pI?

pH < pI. When pH is less than pI, there is an excess amount of H+ in solution. The excess H+ is attracted to the negatively charged carboxylate ion resulting in its protonation. The carbohydrate ion is protonated, making it neutral, leaving only a positive charge on the amine group.