Peptide-mass fingerprint

[2] Once formed, a peptide-mass fingerprint can be used to search in databases for related protein or even genomic sequences, making it a powerful tool for annotation of protein-coding genes.

[7] Another method commonly used that combines both the isolation and digestion steps is SDS-PAGE, a form of electrophoresis that separates and fractionates proteins simultaneously.

While it can be analyzed to some degree on its own, in forming a peptide-mass fingerprint, the peak list is run through a database search to find homologous peptide sequences.

[11] The MASCOT software uses an algorithm that looks for significant peptide sequence homology to present the most statistically likely protein in the sample, based on the results.

Such databases include, among others, Swissprot, often used when researching well characterized organisms like humans, mice, and yeasts; and NCBInr for more general, robust searches.

Some specific examples of how it has been used in the field are as follows: The authors of this study sought to determine which yeasts were metabolically active at lower temperatures and could therefore be used for colder industrial processes.

They grew various yeasts on medium at different temperatures, then determined enzyme activity by separating proteins on a gel and fingerprinting the individual bands.

After discovering that risperidone did have negative metabolic side effects, they tested membrane proteins for glucose and lipid transport in control and experimental groups by MALDI-TOF and fingerprinting.