Activities of cathepsins B, D, H and L in rat heart atrial and ventricular muscle

Activities of four lysosomal proteolytic enzymes, namely cathepsins B, D, H and L are 1.8 to 2.8 times greater in atria of 360 g rats compared with ventricles. Activities of acid phosphatase and β-acetylglucosaminidase (both lysosomal enzymes) are not significantly different in atria and ventricles. Catheptic activities thus reflect the greater protein turnover rate in atria.