Enzymes identified in heart contractions

PITTSBURGH, April 15 (UPI) -- U.S. scientists say they've discovered the previously unknown roles of two enzymes involved in heart muscle contractions.

University of Pittsburgh and University of Chicago researchers said their findings might lead to less-taxing heart disease treatments.

Experiments on slivers of heart muscle revealed contractions can be regulated by the enzymes histone acetyltransferases, or HATs, and histone deacetylases, or HDACs, said Pittsburgh Professor Sanjeev Shroff. He and research associate Stephen Smith collaborated in the study with Chicago Associate Professor Mahesh Gupta and his research associate Sadhana Samant.

The team found that HATs and HDACs influence acetylation of certain heart muscle proteins during a process in which a cluster of atoms called an acetyl group attach to a protein, changing its function.

HATs facilitate acetylation, and HDACs remove the acetyl group.

The team discovered that acetylation renders the muscle fiber more sensitive to calcium, which causes the muscle to contract.

"This is a completely new process in the area of heart muscle contraction," Shroff said. "Acetylation is widely known to regulate such events inside the cell nucleus as gene regulation, but it's never before been associated with heart muscle contraction."

The research is detailed in the Journal of Biological Chemistry.