Relationship between myosin isoenzyme composition, hemodynamics, and myocardial structure in various forms of human cardiac hypertrophy.

Hemodynamic and angiographic parameters, muscle fiber diameter, nonmuscle tissue content, and myosin light chain isoform composition were determined in the left ventricle of nine patients with primary (four with hypertrophic, five with dilated cardiomyopathy) and 27 patients with secondary hypertrophy (11 with aortic regurgitation, 16 with aortic stenosis), nine patients with coronary heart disease, and seven controls. In various forms of hypertrophy, a new atrial-like light chain 1 occurred in two-dimensional electrophoresis of total tissue homogenates amounting up to 29% of total light chain 1. Total light chain 1 content remained constant in all groups when related to tropomyosin.

Myosin isoenzymes in human hypertrophic hearts. Shift in atrial myosin heavy chains and in ventricular myosin light chains.

The myosin light chain complement and proteolytic peptide patterns of myosin heavy chains were studied by two-dimensional and one-dimensional electrophoretic techniques respectively, in a total of 57 samples from ventricular and atrial tissues of normal and hypertrophied human hearts. Hypertrophies were classified haemodynamically as due to pressure-overload and volume-overload. In addition to the occurrence of ventricular light chains in hypertrophied atria we also observed the atrial light chain-1 (ALC-1) in hypertrophied ventricular tissues.

Isoforms of heavy and light chains of cardiac myosins from rat and rabbit.

The light chains of myosin from atrial and ventricular tissues from rat and rabbit were examined by one- and two-dimensional polyacrylamide gel electrophoresis. The myosin heavy chains were electrophoretically isolated, digested after denaturation in sodium dodecyl sulfate with papain and proteinase from S. aureus V8, and the resulting peptides resolved in one-dimensional gel electrophoresis.

Electrophoretic analyses of atrial and ventricular cardiac myosins from foetal and adult rabbits.

1. Rabbit cardiac myosins from atrium and ventricle were found to differ in their native form in pyrophosphate gel electrophoresis as well as in their light chain pattern in one- and two-dimensional electrophoretic systems. 2.

Calcium-regulated biosynthesis of the parathyroid secretory protein, proparathyroid hormone, and parathyroid hormone in dispersed bovine parathyroid cells.

Dispersed bovine parathyroid cells were incubated in vitro with 3H-labeled amino acids for 30--120 min. Analysis of cell extracts by sodium dodecyl sulfate-urea-polyacrylamide gel electrophoresis revealed a calcium-regulated incorporation of 3H-labeled amino acids into three major peaks, one with a molecular weight (Mr) of 70,000 and two peaks in the 10,000 Mr region, and a minor 5,000 Mr peak. Furthermore, [3H]mannose was incorporated into the 70,000 Mr peak, which corresponds to the parathyroid secretory protein (PSP) recognized as a glycoprotein.