Peptidoglycan, M. luteus (PGN)

Peptidoglycan is a polymer of glycopeptide linking N-acetyl or N-glycorylmuramic acid and peptide containing D-amino acid, and is a constituent of the cell wall in most prokaryotes.  It is known that this substance is pyrogenic and initiates a variety of physiological activities such as pyrogenicity and reactivity with SLP Reagent body fluid from silkworm.

Peptidoglycan or murein is a polymer consisting of sugars and amino acids that forms a mesh-like layer outside the plasma membrane of most bacteria, forming the cell wall. The sugar component consists of alternating residues of β-(1,4) linked N-acetylglucosamine (NAG) and N-acetylmuramic acid (NAM). Attached to the N-acetylmuramic acid is a peptide chain of three to five amino acids. The peptide chain can be cross-linked to the peptide chain of another strand forming the 3D mesh-like layer.[3] Peptidoglycan serves a structural role in the bacterial cell wall, giving structural strength, as well as counteracting the osmotic pressure of the cytoplasm. Peptidoglycan is also involved in binary fission during bacterial cell reproduction.
The peptidoglycan layer is substantially thicker in Gram-positive bacteria (20 to 80 nanometers) than in Gram-negative bacteria (7 to 8 nanometers).[4] Depending on pH growth conditions, the peptidoglycan forms around 40 to 90% of the cell wall's dry weight of Gram-positive bacteria but only around 10% of Gram-negative strains. Thus, presence of high levels of peptidoglycan is the primary determinant of the characterisation of bacteria as Gram-positive.[5] In Gram-positive strains, it is important in attachment roles and serotyping purposes.[6] For both Gram-positive and Gram-negative bacteria, particles of approximately 2 nm can pass through the peptidoglycan.[7]

Source:
Micrococcus luteus

Appearance:
Transparent or slightly white-colored suspension in water

Concentration:
~1ug/ml

Potency:
As Reported

Isolation Method:
The substrate is isolated from cultured M. luteus by treatment of hot TCA, followed by trypsin digestion. After sonication of isolated substance, the resultant substrate is suspended in sterilized distilled water.

Notes:
1. SLP Reagent is an in vitro test reagent for peptidoglycan and/or (1->3)-beta-D-glucan detection, utilizing a self-defense mechanism of silkworm which consists of prophenoloxidase activation cascade and subsequent melanin formation in the body fluid.
2. The concentration of peptidoglycan in water is prepared as follows: 
Weigh dry peptidoglycan, followed by its suspension in sterilized distilled water at 1mg/ml concentration. Diluted 1000 x with sterile, distilled water.
3. Potency, expressed by ug/ml, is defined as reactivity to SLP reagent, with the value determined by use of our original peptidoglycan preparation as a reference material.

Caution:
Peptidoglycan is insoluble in water and exists as a precipitate in the suspension. Upon use of the peptidoglycan suspension, the suspension should be mixed well by inversion of the vial and subsequent, vigorous vortexing.

Storage and Stability:
May be stored at 4°C. For long-term storage, aliquot and store at 4°C. Do not freeze. Aliquots are stable for 6 months after receipt. For maximum recovery of product, centrifuge the original vial prior to removing the cap. Further dilutions can be made in assay buffer.