SERVA Lysozyme from chicken egg white, 2.5g

(Muramidase, Mucopeptide-glycohydrolase, Mucopeptide N-acetyl-muramoylhydrolase)

EC 3.2.1.17 • Mr ca. 14 400 • CAS [12650-88-3]

Lysozyme hydrolyzes the β 1 → 4 linkages of the murein between N-acetylmuramic acid and N-acetyl-D-glucosamin, and degrades the heteroglycan chain to disaccharides. This reaction leads to cell lysis in most gram positive bacteria e.g. Micrococcus luteus. Lysis can be prevented if the reaction is performed in an isotonic sucrose medium. Under these assay conditions protoplasts are produced which no longer have a cell wall. The lysis of Micrococcus luteus cells is used for the activity testing of lysozyme. In gram negative bacteria a compact lipopolysaccharide layer on the exposed murein sacculus efficiently shields them from lysozyme digestion. Only when the stabilizing Ca2+ ions are removed by treatment with e.g. EDTA, the murein becomes susceptible to lysozyme. Suitable for hydrolysis of bacterial cell walls and of proteoglycans (1, 2).

(X-Gal)

C14H15BrClNO6 • Mr 408.6 • CAS [7240-90-6]

X-Gal is a well known histochemical substrate used to detect the β-galactosidase enzyme (1, 2, 3, 4, 9, 10). Identification of lacf-colonies (8). X-gal is used to distinguish recombinant plasmids from parental vectors in cloning experiments using vectors containing the lacZ or lacZ [DMvP1](-)peptide gene (2, 3, 5). Upon hydrolysis, X-Gal yields a localized, insoluble blue precipitate making it exceptionally useful in blotting, immunocytochemical, and ELISA assays. X-Gal has been used for the detection of coliforms (E. coli) in municipal water supplies (6) and food products (7). X-Gal is often used in conjunction with IPTG (Isopropyl-β-D-thiogalactopyranoside, cat. no. 26600) which binds and inhibits the lac repressor thus inducing β-galactosidase activity.

Stock solution: 20 mg/ml in DMF. Store in aliquots at -20 °C in the dark. For detection of transformants, use in final concentration of 40 µg/ml.