Xanthine

Milk fat contains an enzyme called xanthine oxidase (XO), some of which survives the pasteurization process and, thanks to homogenization, is now able to pass through the gut wall into the bloodstream intact where it creates havoc by attacking plasmalogen within artery walls. ❋ Unknown (2009)

Theobromine, like caffeine, and also like the asthma drug theophylline, belong to the chemical group known as xanthine alkaloids. ❋ Unknown (2011)

One is completely insoluble in water, which we have termed xanthine, a name which Runge has given to a yellow matter from madder. ❋ George William Septimus Piesse (1851)

In addition, because increasing the excretion of uric acid is additive to the effects of drugs known as xanthine oxidase inhibitors that decrease the production of uric acid, including allopurinol and febuxostat, lesinurad in combination with such drugs has the potential to treat the significant portion of the gout population that is not adequately treated with existing therapies.

Even since 1776 when Scheele found uric acid in urinary calculus, several substances closely related to it such as xanthine, adenine and guanine, etc. have been detected in animal secretions. ❋ Unknown (1966)

Carbon isotope ratios for uracil and xanthine of δ13C = + 44.5‰ and + 37.7‰, respectively, indicate a non-terrestrial origin for these compounds. ❋ Zoe Brain (2008)

"Unless you are referring to a yellow nitrogenous compound, xanthine -" ❋ Anthony, Piers (1996)

It could grow on adenine, guanine, hypoxanthine or xanthine, provided the pyrimidine thymine was added. ❋ Unknown (1988)

The inhibition was reversed by hypoxanthine, adenine, guanine, and xanthine (28). ❋ Unknown (1988)

One is that both hypoxathine and xanthine can be reutilized for nucleic acid synthesis via the enzyme hypoxanthine-guanine phosphoribosyltransferase (HGPRT) (82, 83). ❋ Unknown (1988)

A number of catabolic enzymes were known: nucleases, nucleotidases, nucleosidases, deaminases (for guanine, adenine, adenosine, and adenylic acid), xanthine oxidase and uricase. ❋ Unknown (1988)

The fate of the intermediate oxypurines, hypoxanthine and xanthine, turned out to be a fascinating one. ❋ Unknown (1988)

Thus, the salvage of hypoxanthine and xanthine serves to regulate purine biosynthesis, reducing it when it is excessive. ❋ Unknown (1988)

Xanthine oxidase is responsible not only for the oxidation of 6-MP, but also for the formation of uric acid from hypoxanthine and xanthine (Fig. 4). ❋ Unknown (1988)

Since we knew from metabolic studies that 6-thiouric acid as one of the principal products of 6-MP catabolism, it seemed possible that we could interfere with this oxidation by inhibiting the enzyme responsible for it, xanthine oxidase. ❋ Unknown (1988)

Allopurinol is not only a potent competitive inhibitor of xanthine oxidase, but it is also a substrate (75), the oxidation resulting in the corresponding xanthine analog, oxypurinol (called alloxantine, oxoallopurinal, or oxipurinol in early papers) which is also a xanthine oxidase inhibitor (Fig. 4). ❋ Unknown (1988)

To test for xanthine oxidase inhibition in vivo, we chose a compound that had no inhibitory effects on bacteria or tumors, was non-toxic, but which was ❋ Unknown (1988)

In the early days of seeking antimetabolites for the natural purines in our laboratory, xanthine oxidase had been one of test enzymes. ❋ Unknown (1988)

The single product present in highest amount was 6-thiouric acid, formed by the action of xanthine oxidase in 6-MP. ❋ Unknown (1988)