Hypoxanthine phosphoribosyltransferase (inosine monophosphate: pyrophosphate phosphoribosyltransferase EC 2.4.2.8) has been purified SO-fold from an acid-treated lysate of human erythrocytes. The average particle weight of the enzyme was estimated by gel filtration at 60,000. Between the pH values of 7.1 and 9.1 no marked difference in the initial velocity of IMP synthesis was observed. Kinetic...

Hypoxanthine arabinoside pharmacokinetics were measured during an adenine arabinoside continuous intravenous infusion and during hemodialysis in a patient with renal failure. Therapeutic guidelines for adenine arabinoside in renal failure are provided based on an elimination half-life of 4.7 h and a plasma clearance of 87.9 ml/min for the hypoxanthine metabolite.

Hypoxanthine-guanine phosphoribosyltransferase from Chinese hamster brain, liver, and V79 tissue culture cells appears to have identical structural and catalytic properties. The enzyme has been purified 540-fold to apparent homogeneity from Chinese hamster brain. The native molecular weight is 78,000 to 85,000 determined by Sephadex G-100 column chromatography and acrylamide gel electrophoresis...

The mechanism of reaction of human erythrocyte hypoxanthine-guanine phosphoribosyltransferase was investigated by initial velocity, product inhibition, and isotope exchange studies. Although initial velocity data are compatible with a mechanism involving binary enzyme-substrate complexes, the product inhibition and isotope exchange studies indicate that the reaction is ordered with the formatio...

A method for determining the total content of the oxypurines xanthine and hypoxanthine in urine is described which is technically simplified and has greater specificity than existing methods. This method is highly specific, reproducible, and accurate. It also allows an estimation of the present xanthine and hypoxanthine in the urine without performing any additional measurements.When applied to...

Archaeal family-B DNA polymerases interact specifically with uracil and hypoxanthine, stalling replication on encountering these deaminated bases in DNA template strands. The present review describes X-ray structural data which elucidate the mechanism of read-ahead recognition of uracil and suggests how this is coupled to cessation of polymerization. The possible role of read-ahead recognition ...

1. The activities of the purine phosphoribosyltransferases (EC 2.4.2.7 and 2.4.2.8) in purine-analogue-resistant mutants of Schizosaccharomyces pombe were checked. An 8-azathioxanthine-resistant mutant lacked hypoxanthine phosphoribosyltransferase, xanthine phosphoribosyltransferase and guanine phosphoribosyltransferase activities (EC 2.4.2.8) and appeared to carry a single mutation. Two 2,6-di...

We describe a convenient method for the separation and quantification of xanthine, hypoxanthine, and uric acid in 20 microL of cerebrospinal fluid (CSF) with use of HPLC and ultraviolet detection. The analysis is performed on a Sepharon SGX C18 column and the elution system consists of potassium phosphate buffer, pH 5.1, with 20 mL/L methanol. The lower limit of detection was 4 pmol for hypoxan...

The transplantable murine Dunn osteosarcoma has no detectable hypoxanthine:guanine phosphoribosyltransferase (EC 2.4.2.8) activity. This was established from the tumors directly and from tissue culture cell lines derived from the tumor using a variety of assays: e.g., no [3H]hypoxanthine uptake into tumor or tissue culture cells, no conversion of [3H]hypoxanthine to [3H]IMP by cell extracts fro...

DNA is constantly damaged by endogenous and environmental influences. Deaminated adenine (hypoxanthine) tends to pair with cytosine and leads to the A:T→G:C transition mutation during DNA replication. Endonuclease V (EndoV) hydrolyzes the second phosphodiester bond 3' from deoxyinosine in the DNA strand, and was considered to be responsible for hypoxanthine excision repair. However, the downstr...