Creatinine

Introduction

Creatinine is a nonprotein nitrogenous compound found in the blood and excreted by glomerular filtration at a constant rate (Feher 2012).

Source

Creatinine is derived from nonenzymatic degradation of creatine phosphate which is a phosphagen for vertebrate animals. Phosphagens are high-energy phosphate compounds which supply immediate but limited energy during sudden demand for skeletal muscle and brain. Creatine phosphate is a phosphagen for vertebrate animals, whereas arginine phosphate is the phosphagen for invertebrate animals.

Adenosine triphosphate (ATP) is the energy currency of the cell required for many biochemical reactions. During the sudden demand for ATP, creatine phosphokinase enzyme catalyzes the transfer of phosphoryl group from creatine phosphate to adenosine diphosphate (ADP) to produce adenosine triphosphate (ATP). This reaction is known as Lohman’s reaction.

$$ \mathrm{Creatine}\ \mathrm{Phosphate}+\mathrm{ADP}\rightleftharpoons...