Isozyme-specific enzyme inhibitors. 11. (L-homocysteine)-ATP S-C5' covalent adducts as inhibitors of rat methionine adenosyltransferases

1986 ◽  
Vol 29 (6) ◽  
pp. 1030-1038 ◽  
Author(s):  
Francis Kappler ◽  
Ton T. Hai ◽  
Robert J. Cotter ◽  
Karen J. Hyver ◽  
Alexander Hampton
Keyword(s):  
Enzyme Inhibitors ◽  
Specific Enzyme ◽  
Covalent Adducts

Specific enzyme inhibitors in vitamin biosynthesis. Part II. Revised structures for some 8-substituted pyrido[2,3-d]pyrimidines

1974 ◽  
pp. 1225 ◽  
Author(s):  
Hamish C. S. Wood ◽  
Roger Wrigglesworth ◽  
David A. Yeowell ◽  
Frederick W. Gurney ◽  
B. Stuart Hurblert
Keyword(s):  
Enzyme Inhibitors ◽  
Specific Enzyme

In vivo studies on the conversion of m-tyrosine to 3,4-dihydroxyphenylalanine in the rat

1977 ◽  
Vol 55 (10) ◽  
pp. 1103-1107 ◽  
Author(s):  
J. H. Tong ◽  
R. G. Smyth ◽  
N. L. Benoiton ◽  
A. D'Iorio
Keyword(s):  
Rat Brain ◽  
Enzyme Inhibitors ◽  
Phenylalanine Hydroxylase ◽  
Intraperitoneal Administration ◽  
In Vivo Studies ◽  
Dopa Decarboxylase ◽  
Decarboxylase Inhibitor ◽  
Specific Enzyme ◽  
Dihydroxyphenylacetic Acid

The question whether m-tyrosine can give rise to catechols in vivo has been investigated using labelled precursor. DL-[2-l4C]m-tyrosine (38 μCi/mmol (1 Ci = 37 GBq)) was synthesized from [2-14C]glycine. Radioactive catechols in rat brain, liver, and kidneys were examined 15 min after intraperitoneal administration of DL-[2-14C]m-tyrosine (100 mg/kg). The kidney was the only organ which showed demonstrable amounts of radioactive catechols, and about 14% of the catechols formed was identified as 3,4-dihydroxyphenylalanine (dopa), 22% as 3,4-dihydroxyphenylacetic acid, and 56% as dopamine. However, when the animals were pretreated with dopa decarboxylase inhibitor, labelled catechols were also observed in liver and brain, and dopa accounted for over 95% of the catechols formed in all three organs examined. Thus it is clear that m-tyrosine can be hydroxylated in vivo. Results from experiments using [2-14C]m-tyrosine enantiomers and specific enzyme inhibitors suggest that phenylalanine hydroxylase could be the enzyme catalyzing this reaction.

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