The simultaneous determination of L tyrosine and L lysine, by enzyme supported flow injection analysis (FIA) was developed using two enzyme reactors in parallel and a single oxygen electrode. L-Tyrosine and L-lysine were determined using the enzyme Ltyrosinase (EC 1.14.18.1) and L-lysineLY -oxidase (LysOD, EC 1.4.3. -), respectively. When sample solutions were simultaneously injected into the t...

The data obtained in these experiments show that the nitrile nitrogen of dhurrin is directly derived from the a-amino group of L-tyrosine. This is analogous to the retention of the a-amino nitrogen of valine on its conversion to linamarin (6). The biosynthetic route from L-tyrosine to dhurrin must involve the modification of the amino acid in a manner such that the C&z-N unit remains intact. 15...

The chemiluminescence (CL) signal immediately appeared when a hydrogen peroxide solution was injected into an iron-phthalocyanine tetrasulfonic acid (Fe-PTS) aqueous solution. Moreover, the CL intensity of Fe-PTS decreased by adding l-tyrosine. Based on these results, the determination of trace amounts of l-tyrosine was developed using the quenching-chemiluminescence. The calibration curve of l...

Catecholamines (CA) were studied in peripheral human lymphocytes in basal conditions as well as after L-tyrosine and/or acetylcholine (ACh) stimulation. Nicotinic and muscarinic receptor activation and blockade were assessed. CA were determined after ultrasonic cell disruption in peripheral lymphocytes after incubation (1 h at 37 degrees C) with the chemicals employed. L-tyrosine significantly ...

A new TLC separation and quantitation method for L-tyrosine and L-Dopa mixtures was developed. The minimum tyrosine and Dopa quantities which can be measured by this technique are 0.7 and 1.5 μg respectively. The method may be used to measure the kinetic parameters of polyphenoloxidase as well as to trace the enzyme catalyzed conversion of L-tyrosine into L-Dopa. For a set of 20 measurements th...

Tyrosyl-tRNA synthetase (TyrRS) from Escherichia coli was engineered to preferentially recognize 3-iodo-L-tyrosine rather than L-tyrosine for the site-specific incorporation of 3-iodo-L-tyrosine into proteins in eukaryotic translation systems. The wild-type TyrRS does not recognize 3-iodo-L-tyrosine, because of the bulky iodine substitution. On the basis of the reported crystal structure of Bac...

Introduction: Astrocyte dysfunction is the common pathology resulting in failure of astrocyte-neuron interaction in neurological diseases, including Parkinson’s Disease (PD). To date, only few experimental models of selective ablation of astrocytes are known. The aim of present study was to evaluate the effect of striatal injections of selective glial toxin L-aminoadipic acid (L-AA) on the loco...

1. 72 hour isolated chick hearts show an increase in pulsation rate when placed in M/1000, M/10,000, and M/50,000 l-tyrosine solutions. The optimal effect is seen in M/10,000 and M/50,000 l-tyrosine. 2. All hearts show disturbance of rhythm either in the form of irregular rhythm or heart block. 3. 62 hour isolated chick hearts are not susceptible to l-tyrosine while 96 hour hearts are markedly ...