In general, the DNA in genes codes for the manufacture
of proteins by the cellular protein synthesizing
Genes encoded by the DNA are converted into
proteins selectively during development, such that only
a subset of genes is being actively transcribed (read
into messenger RNA molecules) and translated (converted
into proteins) at any given time.
Thus, while an
individual organism’s genotype is more or less fixed and
constant in all of its cells, the proteome, or sum of
all the proteins currently present, varies by cell type,
developmental stage, and environmental conditions.
Proteomics is the study of the proteins that are
produced by an organism or cell under various
Since tens of thousands of different
proteins can be produced by an organism, proteomics
employs techniques to first separate and then identify
each of these proteins in an extracted sample.
Information about the proteins that are present can be
linked with metabolic pathways to shed light on the
types of processes that are occurring in the cells and
to regulation of the genes that encode the proteins.