Bio-Rad ProteinChip Matrices - Manual (Page 2)

Introduction
ProteinChip energy absorbing molecules (EAM) are an
essential component of successful ProteinChip SELDI
system experiments. EAM is a generic name for
molecules that assist in desorption and ionization of the
analyte. Known as “matrix” in traditional MALDI mass
spectrometry, EAM are applied in organic solvent,
solubilizing many proteins on the array surface. As the
EAM dry, the proteins cocrystallize with the EAM. These
crystals absorb the laser energy and generate the ionized
proteins detected by the ProteinChip SELDI system.
Product Description
Bio-Rad offers three EAM for the detection of proteins
and peptides. The general guidelines for choosing EAM
are based on the molecular weight (MW) and chemical
nature of the analyte, but there are no absolute rules.
ProteinChip CHCA EAM, 5 mg/vial
ProteinChip alpha-cyano-4-hydroxy cinnamic acid
(CHCA) EAM (MW 189.2) are especially good for small
molecules, 1–30 kD.
ProteinChip SPA EAM, 5 mg/vial
ProteinChip sinapinic acid (SPA) EAM (MW 224.2)
are recommended for all larger proteins, but also
work reasonably well for peptides. In general,
© 2006 Bio-Rad Laboratories, Inc.