Variability in the ratio of mutant to wildtype myosin heavy chain present in the soleus muscle of patients with familial hypertrophic cardiomyopathy.A new approach for the quantification of mutant to wildtype protein

The ratio of mutant to wildtype myosin heavy chain (beta-isoform, beta-MHC) in the soleus muscle of patients with familial hypertrophic cardiomyopathy was determined by a combination of HPLC, mass spectrometry and capillary z one electrophoresis, In two patients, one with a Val 606 Met mutation and a nother with a Gly 584 Arg mutation, the fraction of mutant beta-MHC was onl y 12 +/- 6% and 23 +/- 0.7% of total beta-MHC, respectively. These results demonstrate the necessity to determine the ratio of mutant to wildtype prot ein for the interpretation of functional studies on biopsy material from he terozygous patients with an inherited disease. (C) 1999 Federation of Europ ean Biochemical Societies.