TOOLS OF GENETI ENGINEERING -
BASIC REQUIREMENTS II
MASS SPECTROMETRY
In 1900, for the rst time J.. Thomson introduced
mass spectrometer which employed xed
magnetic and electric elds to separate ions of
di erent mass and energy. He recognised that
charged particles di ering in momentum
behaved di erently in an electric eld, and used
this property for separation of ions with di erent
mass.
During 1980s its extensive use for research in
various eld of biological science was started.
During 1990-2000, mass spectrometry became
an important technique for genomics and
proteomics
research leading to the 2002 Nobel Prize in
Chemistry to J.B. Fenn and K. Tanaka. Two-
dimensional electrophoresis is more powerful
when coupled with MS. The unknown protein
spot is cut from the gel and cleaved by trypsin
digestion into fragments which are then analysed
ff fi ff fi ff fi fi fi ff
, by mass spectrometer and the mass of fragment
is plotted. This mass nger print can be used to
estimate the probable amino acid composition of
each fragment and tentatively identify the
protein. The proteome and its changes can be
studied very e ectively by employing the two
techniques together.
The MS can also provide valuable information
about covalent modi cation of proteins which
can a ect their activity. Mass spectrometry is
very useful technique. It is used in identi cation
of unknown compounds, quanti cation of known
compounds and determination of structural and
chemical properties of compounds when present
in small amount (10 - 10° g). This technique
involves: (1) the production of ions of the
materials in sample, (in) their separation on the
basis of their mass : charge (m : e) ratio, and (ili)
determination of relative abundance of each ion.
Therefore, a mass spectrophotometer consists
of three components : the source of ion, an
analyser, and a detector. It does not directly
measure the molecular mass but detects m : e
ratio. Mass is measured in terms of Dalton (Da).
One Dalton = 1/12' of mass of a single atom of
ff ff fifi fi fi
BASIC REQUIREMENTS II
MASS SPECTROMETRY
In 1900, for the rst time J.. Thomson introduced
mass spectrometer which employed xed
magnetic and electric elds to separate ions of
di erent mass and energy. He recognised that
charged particles di ering in momentum
behaved di erently in an electric eld, and used
this property for separation of ions with di erent
mass.
During 1980s its extensive use for research in
various eld of biological science was started.
During 1990-2000, mass spectrometry became
an important technique for genomics and
proteomics
research leading to the 2002 Nobel Prize in
Chemistry to J.B. Fenn and K. Tanaka. Two-
dimensional electrophoresis is more powerful
when coupled with MS. The unknown protein
spot is cut from the gel and cleaved by trypsin
digestion into fragments which are then analysed
ff fi ff fi ff fi fi fi ff
, by mass spectrometer and the mass of fragment
is plotted. This mass nger print can be used to
estimate the probable amino acid composition of
each fragment and tentatively identify the
protein. The proteome and its changes can be
studied very e ectively by employing the two
techniques together.
The MS can also provide valuable information
about covalent modi cation of proteins which
can a ect their activity. Mass spectrometry is
very useful technique. It is used in identi cation
of unknown compounds, quanti cation of known
compounds and determination of structural and
chemical properties of compounds when present
in small amount (10 - 10° g). This technique
involves: (1) the production of ions of the
materials in sample, (in) their separation on the
basis of their mass : charge (m : e) ratio, and (ili)
determination of relative abundance of each ion.
Therefore, a mass spectrophotometer consists
of three components : the source of ion, an
analyser, and a detector. It does not directly
measure the molecular mass but detects m : e
ratio. Mass is measured in terms of Dalton (Da).
One Dalton = 1/12' of mass of a single atom of
ff ff fifi fi fi
