What is a crystalline, nitrogenous substance, closely related to xanthin and uric acid, widely distributed through the animal body, but especially in muscle tissue; -- called also sarcin, sarkin called?

hypoxanthin — A crystalline, nitrogenous substance, closely related to xanthin and uric acid, widely distributed through the animal body, but especially in muscle tissue; -- called also sarcin, sarkin. (Webster's 1913.)

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