The picture of L-tyrosine metabolism obtained from isotope experiments and other studies on intact animals is still incomplete. Either p-hydroxyphenylpyruvate or 2:5-dihydroxyphenylalanine may be the first intermediate, since either could form the second postulated intermediate, 2:5-dihydroxyphenylpyruvate (Neubauer, 1909), and both are converted to homogentisic acid by alcaptonurics (Neuberger...

An extracellular phosphatase was purified to homogeneity from the entomopathogenic fungus Metarhizium anisopliae with a 41.0% yield. The molecular mass and isoelectric point of the purified enzyme were about 82.5 kDa and 9.5 respectively. The optimum pH and temperature were about 5.5 and 75 degrees C when using O-phospho-L-tyrosine as substrate. The protein displayed high stability in a pH rang...

Endothelin-1 (ET-1) has been implicated in coronary vasospasm by enhancing coronary vasoconstriction to vasoactive eicosanoids, and a role for protein kinase C (PKC) activation has been suggested. However, the cellular mechanisms downstream from PKC activation are unclear. We investigated whether physiological concentrations of ET-1 enhance coronary smooth muscle contraction by activating a PKC...

The laser-induced fluorescence spectrum of jet-cooled L-tyrosine exhibits more than 20 vibronic bands in the 35450-35750 cm(-1) region. We attribute these bands to eight conformers by using results of UV-UV hole-burning spectroscopy. These isomers are classified into four groups; each group consists of two rotational isomers that have a similar side-chain conformation but different orientations...

The study was focused on the effect of drought and waterlogging stresses in two-year pot experiments peat substrate content glucose, fructose sucrose free amino acids potato tubers four cultivars (yellow-fleshed Laura, Marabel, Milva blue-fleshed Valfi) after 71 days exposure to conditions (BBCH 909). Drought increased levels fructose, three except for cv. Laura. stress l-proline (+248.4%), l-h...

Dual biosynthetic pathways diverge from prephenate to L-tyrosine in Pseudomonas aeruginosa, with 4-hydroxyphenylpyruvate and L-arogenate being the unique intermediates of these pathways. Prephenate dehydrogenase and arogenate dehydrogenase activities could not be separated throughout fractionation steps yielding a purification of more than 200-fold, and the ratio of activities was constant thro...

Stereochemical studies on tyrosine phenol-lyase from Escherichia intermedia have shown that the alpha, beta-elimination reactions of L-serine and D- and L-tyrosine proceed with retention of configuration at C-beta. Stereospecifically beta-tritiated L-serine is slowly racemized at C-beta. Deuterium from the alpha-position of L-tyrosine is partially transferred to C-4 of the phenol formed when th...

Tyrosine decarboxylase (TDC, EC 4.1.1.25) is an enzyme that catalyzes the decarboxylation of l-tyrosine to produce tyramine and CO2. In this study, a 1881-bp tdc gene from Lactobacillus brevis was cloned and heterologously expressed in Escherichia coli BL21 (DE3). Glucose was discovered to play an important role in the soluble expression of rLbTDC. After optimization, recombinant TDC (rLbTDC) w...