We characterized the dependence of the 229 nm Raman cross sections of tyr and trp on solvent exposure in native horse and tuna cytochrome c and in horse and sperm whale myoglobin. Tyr and trp residues with larger solvent accessible surface areas have smaller 229 nm excited tyr and trp Raman cross sections. We observe that in water-propanol solvent mixtures the 229 nm excited tyr and trp Raman c...

We report evidence that a porphyrinic microsensor for detection of nitric oxide (NO) also detects biologically relevant concentrations of tyrosine (Tyr) in dog brain. Tyr is oxidized by this sensor at the same potential as NO, and the sensitivity for NO and Tyr are of the same order of magnitude. The interference from Tyr is of importance because 1) Tyr is abundant and 2) there is a concentrati...

The Mycobacterium tuberculosis enzyme Rv2275 catalyzes the formation of cyclo(L-Tyr-L-Tyr) using two molecules of Tyr-tRNA(Tyr) as substrates. The three-dimensional (3D) structure of Rv2275 was determined to 2.0-Å resolution, revealing that Rv2275 is structurally related to the class Ic aminoacyl-tRNA synthetase family of enzymes. Mutagenesis and radioactive labeling suggests a covalent interme...

This study aimed to investigate the potential use of microalgae Chlorella sorokiniana and Scenedesmus quadricauda for bioremediation olive mill wastewater (OMW), which is a major environmental issue waste product oil production. The investigated effects different dilutions (10% 50%) OMW on growth their ability remove phenolic component hydroxytyrosol (OH-Tyr) enhance antioxidant properties. res...

Studies on the single Cu protein galactose oxidase (68kDa; 639 amino acids) from Fusarium NRRL 2903 are described. The Cu is coordinated in a square based pyramid by Tyr-272, Tyr-495 (axial), His-496, His-581 and H20 (the substrate binding site), and the enzyme functions as a 2-equivalent oxidase, 0, + H,O,, with oxidation of primary alcohol substrates RCH20H to RCHO. The active enzyme has a co...

Cyclooxygenases (COXs) are heme-containing sequence homodimers that utilize tyrosyl radical-based catalysis to oxygenate substrates. Tyrosyl radicals are formed from a single turnover of substrate in the peroxidase active site generating an oxy-ferryl porphyrin cation radical intermediate that subsequently gives rise to a Tyr-385 radical in the cyclooxygenase active site and a Tyr-504 radical n...

Injury of articular cartilage leads to an imbalance in tissue homeostasis, and due the poor self-healing capacity affected often exhibits osteoarthritic changes. In recent years, injectable highly tunable composite hydrogels for engineering drug delivery have been introduced as a desirable alternative invasive treatments. this study, we aimed formulate by combining different concentrations hyal...

To study its contribution to the assembly of the green plant manganese stabilizing protein (MSP) into photosystem II (PSII), tyrosine residues were specifically acetylated using N-acetylimidazole (NAI). In soluble MSP, three groups of Tyr residues could be differentiated by NAI acetylation: approximately 5 (actually approximately 5.2) Tyr residues could be easily acetylated (superficial), 1-2 T...

When T cells are activated via the T cell receptor (TCR) complex a number of cellular substrates, including some cell surface proteins, become phosphorylated on tyrosine (Tyr) residues. Phosphorylation of cytoplasmic Tyr renders these cell surface receptors competent to interact with proteins that link cell surface receptors to protein in the intracellular signaling pathways. Here we show that ...

BACKGROUND/AIMS The biological effects of periodic mechanical stress on chondrocytes have been studied extensively over the past few years. However, the mechanisms underlying chondrocyte mechanosensing and signaling in response to periodic mechanical stress remain to be determined. In the current study, we examined the effects of focal adhesion kinase (FAK) signaling on periodic mechanical stre...