The low tissue concentrations of tetrahydrobiopterin, as well as the antagonism between the catecholamine feedback inhibition of tyrosine hydroxylase and the reduced cofactor concentrations, suggest that dihydropteridine reductase may play an important role in the regulation of catecholamine biosynthesis. The interaction of the different components involved in the hydroxylation of tyrosine was ...

Prolyl 3-hydroxylase activity, expressed per unit of extract protein, was much higher in rat kidney cortex than in the lung, liver or skin. A marked decrease in activity was found in the kidney cortex, liver and skin beyond 10 days of age. The ratio of prolyl 3-hydroxylase to 4-hydroxylase activity in the kidney cortex was 13--17 times that in the skin, that in the liver 6--8 times, and that in...

A human cDNA containing the complete coding sequence for a human tyrosine hydroxylase (EC 1.14.16.2, form 2) was introduced into the genome of Autographa californica nuclear polyhedrosis virus (AcNPV) downstream to the polyhedrin promoter. Infection of Spodoptera frugiperda cells (SF9) with recombinant virus resulted in the expression of human tyrosine hydroxylase in these invertebrate cells. C...

Of 957 patients with type 1 diabetes without known Addison's disease 1.6% (n = 15) were positive for 21-hydroxylase autoantibodies. Among DQ8/DQ2 heterozygous patients, the percentage expressing 21-hydroxylase autoantibodies was 5% (10 of 208) vs. less than 0.5% of patients with neither DQ8 nor DQ2. Three of the diabetic patients found to have 21-hydroxylase autoantibodies on screening were sub...

In vitro microsomal formation of primary metabolites of indinavir (CRIXIVAN, MK-0639, L-735,524), an HIV protease inhibitor, were qualitatively similar among the different developmental stages in humans, although the fetal liver had a lower capability to form the metabolites than the pediatric and adult liver. The lower activity of fetal liver was mainly owing to a decrease in the Vmax values. ...

The metabolism of propranolol was examined by using microsomes from Dark Agouti rats known as a poor-metabolizer animal model for debrisoquine 4-hydroxylation and Wistar rats. Propranolol 4- and 5-hydroxylations followed biphasic Michaelis-Menten kinetics, and 7-hydroxylation and N-desisopropylation were monophasic in both strains. The kinetic studies showed that the Vmax for propranolol 7-hydr...

Frisbee, Jefferson C., John R. Falck, and Julian H. Lombard. Contribution of cytochrome P-450 v-hydroxylase to altered arteriolar reactivity with high-salt diet and hypertension. Am J Physiol Heart Circ Physiol 278: H1517–H1526, 2000.—The present study evaluated the contribution of cytochrome P-450 v-hydroxylase in modulating the reactivity of cremaster muscle arterioles in normotensive rats on...

Tumor directed cytotoxic therapy is one of the major challenges for the success of chemotherapy. In order to accomplish this goal in neuroblastoma, we rationally designed a prodrug of etoposide as substrate for tyrosine hydroxylase, a well established neuroblastoma associated enzyme. Here, we report synthesis and characterization of a 3,4 dihydroxy-phenyl carbamate derivative of etoposide. In o...

We have cloned homologs of the Pseudomonas putida GPo1 alkane hydroxylase from Pseudomonas aeruginosa PAO1, Pseudomonas fluorescens CHA0, Alcanivorax borkumensis AP1, Mycobacterium tuberculosis H37Rv, and Prauserella rugosa NRRL B-2295. Sequence comparisons show that the level of protein sequence identity between the homologs is as low as 35%, and that the Pseudomonas alkane hydroxylases are as...

Membrane-permeable derivatives of cyclic AMP (cAMP) produced concentration-dependent increases in activity of tyrosine hydroxylase (L-tyrosine, tetrahydropteridine:oxygen oxidoreductase (3-hydroxylating), EC 1.14.16.2) in membrane-limited nerve endings (synaptosomes) prepared from three regions of rat brain. Increased hydroxylation occurred even after preincubation and removal of dibutyryl cycl...