Patent ID: 8880353

Claim:
An apparatus for identifying a ribonucleic acid, comprising a memory and a processor, wherein the memory comprises: a peak list that stores the peaks of a spectrum extracted from tandem mass spectrometry data of a ribonucleic acid cleaved by enzymatic cleavage; a ribonucleic acid sequence database that stores ribonucleic acid sequences; and a fragmentation rules table that stores fragmentation rules corresponding to the enzymatic cleavage; and wherein the processor is configured to: extract measured fragment molecular weights from the peaks; fragment a candidate ribonucleic acid sequence from the ribonucleic acid sequence database into fragment sequences by referring to the fragmentation rules; compute theoretical fragment molecular weights for the fragment sequences; extract candidate theoretical fragment molecular weights from the theoretical fragment molecular weights that correspond to the measured fragment molecular weights by comparing the theoretical fragment molecular weights with the measured fragment molecular weights; extract candidate fragment sequences corresponding to the candidate theoretical fragment molecular weights, from the fragment sequences; compute the theoretical product ion masses for the candidate fragment sequences according to predetermined dissociation rules; extract measured product ion masses from the peaks; score the candidate fragment sequences by comparing the theoretical product ion masses with the measured product ion masses to produce scores; and identify fragment sequences of the ribonucleic acid from the candidate fragment sequences based on the scores.