CHEMISTRY GLOSSARY

tyrosine    →   tirozin

Tyrosine is hydrophobic amino acids with aromatic side chain. Tyrosine is large aromatic residue that is normally found buried in the interior of a protein and is important for protein stability. Tyrosine has special properties since its hydroxyl side chain may function as a powerful nucleophile in an enzyme active site (when ionized) and is a common site for phosphorylation in cell signaling cascades. Tyrosine absorbs ultraviolet radiation and contributes to the absorbance spectra of proteins. It is not essential (or semi-essential) to the human diet, since it is synthesized in the body from other metabolites.

• Abbreviations: Tyr, Y
• IUPAC name: 2-amino-3-(4-hydroxyphenyl)propanoic acid
• Molecular formula: C₉H₁₁NO₃
• Molecular weight: 181.19 g/mol

T-S diagram    →   T-S dijagram

The relationship between the temperature (T) and the salinity (S) of a seawater can be illustrated graphically on a T-S diagram, which is a simple, but powerful tool used in studies of seawater density, mixing, and circulation. In a T-S diagram, temperature is plotted along the vertical axis in degrees Celsius and salinity is measured along the horizontal axis in PSU (Practical Salinity Units). Seawater density is illustrated in the diagram by curved lines of constant density (isopycnals). Water tends to move horizontally throughout the deep ocean, moving along lines of equal density.

Chitosan    →   Kitozan

Chitosan is a linear polysaccharide composed of randomly distributed N-acetyl D-glucosamine and D-glucosamine units. It can be easily derived from partial deacetylation of natural polymer chitin. At a minimum deacetylization level of 60 % (amount of free amino groups in the polymer) it is considered to be chitosan. Thanks to the amino groups of D-glucosamine, chitosan can be protonated and turned into polycation, which is one of the sources of unique properties of chitosan as biopolymer, like aqueous solubility, antibacterial properties, biodegradability with non-toxic residues and biocompatibility.