Post-transcriptional modification of serum creatine kinase in infected intensive care patients.

Low creatine kinase (CK) activities in serum are associated with high fatality rates in intensive care patients. The underlying mechanisms for this phenomenon were investigated. No correlation was found with other biochemical markers of inflammation (CRP, alpha-1 acid glycoprotein, alpha-2 macroglobulin). In the patients' serum a factor is described which is capable of increasing the activation energy of normal CK-MM, indicating molecular changes in CK-structure. This factor is likely to be an enzyme which is present in liver tissue and in fibroblasts. Similar results were obtained after in vitro treatment of normal serum samples with arylsulfatase. Furthermore, bacterial strains isolated in the serum of intensive care patients were found to alter human CK structure. In the investigated patient group, changes in CK activation energy are influenced by serum factors other than carboxypeptidase N activity.