[Individual variability and an error in the method of determining protein thermostability]

The individual variability of the heat resistance of two enzymes (aldolase and actomyosine) of the m. gastrochemius of the grass frog Rana temporaria has been quantitatively evaluated by means of analysis of variance. 37--41% of the total variability of the character may be due to errors in the methods of investigation, whereas 59--63% of the variability is due to phenotypic differences between individuals of the same population. The extent of error is primarily associated with the initial stages of the experiment, i. e. the isolation of the enzyme preparations. The individual variability of the heat resistance of proteins is lower than that of the cells or the organisms from which they are derived.