<s>
SEQUEST	B-Application
is	O
a	O
tandem	O
mass	O
spectrometry	O
data	O
analysis	O
program	O
used	O
for	O
protein	O
identification	O
.	O
</s>
<s>
SEQUEST	B-Application
identifies	O
collections	O
of	O
tandem	O
mass	O
spectra	O
to	O
peptide	O
sequences	O
that	O
have	O
been	O
generated	O
from	O
databases	O
of	O
protein	O
sequences	O
.	O
</s>
<s>
SEQUEST	B-Application
identifies	O
each	O
tandem	O
mass	O
spectrum	O
individually	O
.	O
</s>
<s>
The	O
peptide	O
's	O
intact	O
mass	O
is	O
known	O
from	O
the	O
mass	O
spectrum	O
,	O
and	O
SEQUEST	B-Application
uses	O
this	O
information	O
to	O
determine	O
the	O
set	O
of	O
candidate	O
peptides	O
sequences	O
that	O
could	O
meaningfully	O
be	O
compared	O
to	O
the	O
spectrum	O
by	O
including	O
only	O
those	O
near	O
the	O
mass	O
of	O
the	O
observed	O
peptide	O
ion	O
.	O
</s>
<s>
For	O
each	O
candidate	O
peptide	O
,	O
SEQUEST	B-Application
projects	O
a	O
theoretical	O
tandem	O
mass	O
spectrum	O
,	O
and	O
SEQUEST	B-Application
compares	O
these	O
theoretical	O
spectra	O
to	O
the	O
observed	O
tandem	O
mass	O
spectrum	O
by	O
the	O
use	O
of	O
cross	O
correlation	O
.	O
</s>
