Lysozyme

What is Lysozyme?

Lysozyme is a protein found in many human secretions, such as tears, milk, mucus and saliva. The human form of lysozyme has much higher specific activity than other forms of lysozyme such as chicken egg white lysozyme. Human lysozyme is commonly associated with innate immunity, which forms the first line of defense against infections.

The Functions of Lysozyme

Antimicrobial

Lysozyme protects against bacterial infection by breaking down the carbohydrates in bacterial cell walls, killing them. Hence, lysozyme is part of the innate immune response. In saliva it protects the oral cavity from pathogens. In times of increased inflammation, such as during inflammation of the salivary glands or after a tonsillectomy, there is an increase in lysozyme. This protein also works in synergy with the bactericidal properties of lactoferrin, another common protein found in mucosal secretions.

Lysozyme also has fungicidal properties, protecting mucosal areas from invasion by pathogenic yeast or fungi. Lysozyme has been shown to inhibit viral replication and infection such HIV. Lysozyme also interacts with and increases the function of histatin, a protein shown to be bactericidal and fungicidal.

Antioxidant

Lysozyme scavenges free radicals and hydroxyl molecules, leading to decreased oxidative stress.

The Uses of Lysozyme

Cell Lysis

Not only does lysozyme have very important clinical implications but it is also a useful tool in molecular biology. The ability of lysozyme to break down bacterial cell walls (cell lysis) is utilized by molecular biologists. Cell lysis is necessary to extract recombinant proteins or DNA from bacterial cells. Human lysozyme is preferred to chicken lysozyme because it is up to four times more active. Also, the activity of chicken lysozyme has high lot-to-lot variation. Many recombinant protein production systems prefer an animal-free lysozyme to avoid the risk of infectious disease transmission.

Lysobac^TM is InVitria's recombinant human lysozyme that is not only a more active cell lysis reagent, but also animal-free and consistent.

Click here to find out more about Lysobac^TM, the new highly-effective recombinant lysozyme from InVitria.

References:

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Huang J, Wu L, Yalda D, Adkins Y, Kelleher SL, Crane M, Lonnerdal B, Rodriguez RL, Huang N. (2002). Expression of functional recombinant human lysozyme in transgenic rice cell culture. Transgenic Research, 11(3):229-39.

Lee-Huang S, Huang PL, et al. (1999). Lysozyme and RNases as anti-HIV components in beta-core preparations of human chorionic gonadotropin. Proceedings of the National Academy of Sciences of the United States of America, 96(6):2678-81.

Lee-Huang S, Maiorov V, et al. (2005). Structural and functional modeling of human lysozyme reveals a unique nonapeptide, HL9, with anti-HIV activity. Biochemistry, 44(12):4648-55.

Studier FW. (1991). Use of bacteriophage T7 lysozyme to improve an inducible T7 expression system. Journal of Molecular Biology, 219(1):37-44.

Sun X, Salih O, Helmerhorst. (2009). Kinetics of histatin proteolysis in whole saliva and the effect on bioactive domains with metal-binding, antifungal, and wound-healing properties. The FASEB Journal, In Press.

Tenovuo J. (1998). Antimicrobial function of human saliva--how important is it for oral health? Acta Odontologica Scandinavica, 56(5):250-6.