phosphocreatinkatalyse

Phosphocreatin catalysis, known in German as phosphocreatinkatalyse, refers to the biochemical conversion of phosphocreatine and ADP into creatine and ATP. The reaction is mediated by the enzyme creatine kinase, which exists in several isoforms (muscle, brain, heart, and cytosolic variants). Creatine kinase catalyzes a reversible transfer of a phosphoryl group from phosphocreatine to ADP, thereby maintaining cellular ATP levels during brief, high‑energy demands such as muscle contraction or neuronal activity. The reaction is represented by the equation: phosphocreatine + ADP ⇌ creatine + ATP.

The catalytic mechanism involves binding of phosphocreatine and ADP to the enzyme’s active site followed by an essential phosphoryl transfer that yields ATP. Kinetic studies show the reaction follows Michaelis‑Menten kinetics with a Km for phosphocreatine of around 1–2 mM in skeletal muscle. The enzyme’s activity is regulated by phosphorylation of its active site residues and by intracellular pH; under acidic conditions the enzyme is slightly inhibited, helping to buffer pH during intense activity.

Creatine kinase is also a biomarker for muscle injury; elevated plasma levels indicate cellular damage. In addition to its role as a quick ATP buffer, the phosphocreatine system is instrumental in metabolic cross‑talk between tissues, such as shuttle of high‑energy phosphate from mitochondria to sites of ATP utilization. Overall, phosphocreatinkatalyse is a central component of cellular energy homeostasis, especially in tissues with high, fluctuating energy demand.