Deoxycytidylate deaminase, catalyzing the conversion of dCMP to dUMP, is an important enzyme in the de novo synthesis of thymidine nucleotides. It also may be involved in the action, as well as the metabolism of anticancer agents. Recently, several L- and D-configuration pyrimidine deoxynucleoside analogs were found to be potent antiviral and antitumor agents. Their interaction with dCMP deamin...

Mammalian adenosine deaminase has been shown by genetic and biochemical evidence to be essential for the development of the immune system. For the purpose of studying the function and structure of this enzyme, we have isolated by genetic selection a mouse cell line, B-1/50, in which adenosine deaminase levels were increased 4,300-fold over the parent cell line. The enzyme was purified from thes...

Cultured leukemic T-lymphoblasts, incubated in the pres ence of inhibitors of adenosine deaminase, are exquisitely sensitive to growth inhibition by deoxyadenosine. An analogy between this phenomenon and human combined immunodefi ciency disease associated with inborn adenosine deaminase deficiency and the use of inhibitors of adenosine deaminase in the management of T-cell acute lymphoblastic l...

Evidence has been presented that chick embryo deoxycytidylate deaminase (EC 3.5.4.12) is capable of undergoing structural changes under a variety of conditions. Rate studies revealed that inhibition of the enzyme by ethylenediaminetetraacetate markedly diminishes at 10” and below. Although EDTA does not inhibit the deaminase at lo”, the inhibition by urea, N-ethyhnaleimide, and 5,5’dithiobis(Z-...

Cytidine (CR) deaminase was purified 47,000-fold to homogeneity from human placenta. The molecular mass of CR deaminase was estimated to be 48.7 kDa by gel filtration and 16.1 kDa by sodium dodecyl sulfate polyacrylamide gel electrophoresis, suggesting that it contains three or four identical subunits. We determined the amino acid sequence of several peptide fragments and designed 5'-primers to...

To test whether extracellular adenosine participates in the local regulation of intestinal blood flow during nutrient absorption, the serosa of the jejunum was continuously suffused with adenosine deaminase (7 micrograms protein/ml) or theophylline (10(-4) M) in Ringer's solution. Using video microscopy, blood flow was calculated in submucosal arterioles from diameter and red cell velocity meas...

1-Aminocyclopropane-1-carboxylate (ACC) deaminase has been found in various plant growth-promoting rhizobacteria, including rhizobia. This enzyme degrades ACC, the immediate precursor of ethylene, and thus decreases the biosynthesis of ethylene in higher plants. The ACC deaminase of Rhizobium leguminosarum bv. viciae 128C53K was previously reported to be able to enhance nodulation of peas. The ...

L-arginine is conditionally essetcial amino acid, required for normal cell growth, protein synthesis, ammonia detoxification, tissue growth and general performance, proposed in the treatment of men sterility and prevention of male impotence. The aim of the present paper was to estimate the activity of the enzymes of adenine nucleotide metabolism: 5'-nucleotidase (5'-NU), adenosine deaminase (AD...

The double-stranded RNA (dsRNA) adenosine deaminase (DRADA) deaminates adenosine residues to inosines and creates I-U mismatched base pairs in dsRNAs. Its involvement in RNA editing of glutamate-gated ion channel gene transcripts in mammalian brains has been proposed as one of the biological functions for this recently identified cellular enzyme. We purified a mixture of three forms, 93, 88, an...