**2.1 Amino acid sequence determination techniques**

Determination of the amino acid sequence of all or part of a protein or peptide is known as prediction of protein sequence. It is used to categorize the protein and may help in characterizing its post-translational modifications. In a protein, determination of the amino acid sequence involves the following steps [10]:


For determining the composition and the sequence of the protein, two direct methods can be used:


travels to the detector through a flight tube. The ions with lighter mass will reach the detector faster due to Newton's second law (F = ma) and hence, will be detected first. After the spectrum is recorded, it is further analyzed and compared against a database of sequenced proteins. A detailed sequence of protein fragments can be determined by repeating the process with different enzymes for cleavage. As a result, the fragments become much smaller with the fragments overlapping each other establishing the order of the protein.
