2. SEROGENETIC MARKERS
Common Isoenzymes Used for Forensic Protein Profiling
Erythrocyte Isoenzyme Function Protein
Symbol
Number
of Alleles
Phosphoglucomutase transfers a phosphate group on an α-D-glucose monomer from
the 1 to the 6 positions in the forward direction or the 6 to the
1 position in the reverse direction.
PGM 2 (10
allele
detected
in IEF)
Erythrocyte acid
phosphatase
frees attached phosphoryl groups from other molecules during
digestion.
ACP/EAP 2
Esterase D splits esters into an acid and an alcohol in a chemical
reaction with water
ESD 2
Adenylate kinase catalyzes the interconversion of the various adenosine
phosphates (ATP, ADP, and AMP)
AK 2
Glyoxalase I catalyses the conversion of reactive, acyclic alpha-oxoaldehydes
into the corresponding alpha-hydroxyacids.
GLO 2
Adenosine deaminase needed for the breakdown of adenosine from food and for the
turnover of nucleic acids in tissues.
ADA 2
3.
4. Serum Protein Polymorphisms
Serum Protein Function Chromosomal
location
Number of
alleles
Haptoglobin In blood plasma, haptoglobin binds with high
affinity to free hemoglobin released from
erythrocytes, and thereby inhibits its
deleterious oxidative activity.
Hp (16q22.1) 2
Group-specific component Human group-specific component (GC) is the
major vitamin D-binding protein in plasma.
Gc (4q12–13) 2
Transferrin Transferrin is a blood-plasma glycoprotein,
which plays a central role in iron metabolism
and is responsible for ferric-ion delivery.
Tf (3q22.1) 3
Protease inhibitor (α1-
antitrypsin)
Alpha-antitrypsin (AAT) is a serine protease
inhibitor, which inhibits the proteolytic enzyme
elastase (it is an enzyme from the class of
proteases that break down proteins)
Pi (14q32.1) Many
5. HLA antigens and HLA typing
HLA (human leukocyte antigen) is
the human major
histocompatibility complex
(MHC), a multigene family involved
in the defense of humans (and all
vertebrae) against pathogens.
Plays vital role in cell mediated
immunity.
The classical loci, routinely studied
in human medicine, are HLA-A,
HLA-B, and HLA-C for class I, and
HLA-DRB1, HLA-DQB1, and HLA-
DPB1 for class II.
6. HLA class I HLA class I I
polymorphic α-chain
combined with a
monomorphic β-
globulin chain
two polymorphic
chains (α and β)
Expressed on almost
all nucleated cells.
Expressed
constitutively only on
macrophages,
dendritic cells, and B
cells, as well as
activated T cells and
thymic epithelial cells
present endogenously
processed peptides to
CD8+ T
present peptides to
CD4+ T cells.
7. HLA TYPING
Sequence-specific oligonucleotide probe (SSOP)
hybridization
Sequence-specific primers (SSP)
Sequencing-based typing (SBT)
Next generation sequencing (NGS)
DNA Typing Methods: Most HLA typing methods in use are
based on amplification of specific HLA gene portions from
genomic DNA using polymerase chain reaction (PCR).
Editor's Notes
The isoelectric focusing (IEF) technique can be used to separate proteins according to their isoelectric points (pI). The pI is the pH value at which the net electric charge of an amino acid is zero. All proteins are composed of amino acids, and each has its own characteristic pI at which its net electric charge is zero and does not migrate in an electric field
The major histocompatibility complex is a large locus on vertebrate DNA containing a set of closely linked polymorphic genes that code for cell surface proteins essential for the adaptive immune system.
The major histocompatibility complex is a large locus on vertebrate DNA containing a set of closely linked polymorphic genes that code for cell surface proteins essential for the adaptive immune system.
• Sequence-specific oligonucleotide probe (SSOP) hybridization is based on amplification of the most relevant portions of exons 2 and 3 (coding for the peptide-binding domain in class I molecules) or exon 2 (coding for the peptide-binding domain in class II molecules), followed by hybridization (on nylon membranes, plates, or flow cytometry beads) using sequences specific for a certain allele or group of alleles.
• Sequence-specific primers (SSP) use multiple PCR reactions, each specific for an allele or group of alleles. Presence or absence of amplification is detected by electrophoresis. The number of reactions needed depends on locus polymorphism and degree of resolution.
• Sequencing-based typing (SBT) involves sequencing HLA genes and comparing the sequence with published libraries (IMGT/HLA database). Degree of resolution will depend on the length of the sequence obtained. It is the only method with ability to detect and characterize new alleles.
• Next generation sequencing (NGS) methods have recently been applied to HLA typing, increasing throughput and allele identification capabilities, and allowing for easier suitable donor identification.
