In the chemical sphere, much attention is paid to proteins, their functions, and reactions which may influence their existence. Gary Walsh (2009) admits that the vast majority of proteins which are usually “derived from eukaryotic sources, undergo covalent modifications either during their ribosomal synthesis or after synthesis is complete” (p. 1). Due to such abilities of proteins, the rise of post-translational modifications is observed. These types of modifications are characterized by limited applications and inherent to human lactoferrin glycoprotein and other N-linked glycans. Due to the possibilities to influence a number of protein properties, post-translational modifications are under the deep investigation of many scientists who aim at defining the differences between proteins’ structures and functions.
It is necessary to admit that some glycoproteins are characterized by various types of associations, and one of the most spread is the oligosaccharides. “Oligosaccharides are fascinating biomolecules which are gaining in importance at a phenomenal pace compared with other well-studied biomolecules such as proteins and oligonucleotides” (Osborn & Khan 2000, p. 7). The peculiar feature of this type of polymer is the possibility to perform a variety of functions like integral participants of cell-cell recognition or cell-differentiation (Osborn & Khan 2000, p. 9). This is why oligosaccharides are able to be involved into protein trafficking, biological activity, and stability that is cruel for various types of proteins and lactoferrin glycoprotein in particular.
John Hill (2008) says that lactoferrin is the type of glycoprotein that performs a number of important roles in the biology of a human and main found in some secretions from mammals (p.36). Human lactoferrin (LF) may perform various functions of glycoproteins such as inflammatory regulation with the help of which some bioactivities may be improved or, vice versa, be damaged. In fact, the chosen glycoproteins have some kind of therapeutic application, this is why a number of attempts to produce high glycoproteins under specific conditions have been already made and continue developing. Still, the above-mentioned oligosaccharides are based not only on a proper work of lactoferrins. These polymers are usually found in N-linked glycans which may be divided into “intra- and extracellular” types (Tsai 2007, p. 172).
N-linked glycans as the rest of glycans have to be attached to proteins and for the und on cell surface; the glycans under consideration are derived from a core14-sugar element and has to be attached to the group of nitrogen characterized by asparagine. This group is also known as the R-group. As a rule, N-linked glycans perform the functions connected with protein trafficking and hold the most important protein sensors. This is why these glycans promote the increase of stability and restriction of flexibility. To analyze better how the glycans work and cooperate with other components of post-translational modifications, it is offered to rely on the basics of ESI mass spectrometry and the possibilities of electrospray ionization of substances.
ESI (electrospray ionization) mass spectrometry of various peptides is properly studied by a variety of scientists as it allows the peptides be sequenced and modified. Still, the results of ESI mass spectrometry concerning glycans identified are not as successful as it is expected, this is why the loss of some glycans is still possible. Due to a considerable increase of chemical sensitivity that is observed in glycans, the ideas of ESI mass spectrometers become more urgent and obligatory for research. In general, the nature of N-linked glycans and their activities during the process of post-translational modifications is complex indeed, and it is important to use appropriate strategies to improve the conditions analyzed.
References
Hill, JW 2008, Natural treatments for Genital Herpes, Cold Sores and Shingles. Clear Springs Press, Yelm, WA.
Osborn, HM & Khan, TH 2000, Oligosaccharides: Their Synthesis and Biological Roles. Oxford University Press, New York.
Tsai, CS 2007, Biomacromolecules: Introduction to Structure, Function and Informatics. John Wiley & Sons, Hoboken.
Walsh, G 2009, Post-Translational Modification of Protein Biopharmaceuticals. Willey – VCH, Weinheim.