Many enzymes form homooligomers, yet the functional significance of self-association is seldom obvious. Herein, we examine the connection between oligomerization and catalytic function for proline utilization A (PutA) enzymes. PutAs are bifunctional enzymes that catalyze both reactions of proline catabolism. Type A PutAs are the smallest members of the family, possessing a minimal domain archit...

An increase in the H2 S (hydrogen sulphide, hereafter sulphide) concentration in pulmonary artery smooth muscle cells (PASMCs) has been proposed to mediate hypoxic pulmonary vasoconstriction (HPV). We evaluated this hypothesis in isolated rat intrapulmonary arteries (IPAs) by examining the effects of the sulphide precursor cysteine and sulphide-synthesis blockers on HPV and also on normoxic pul...

BACTERIAL INFECTIONS HAVE been one of the major scourges of humankind throughout history. Sepsis is recognized as a global health problem with an increasing incidence (5). The rate of hospitalization for sepsis more than doubled between 2000 and 2008 in the US (16). No monotherapy has been successful in improving mortality, including the recent failure of recombinant activated protein C to show...

Hydrogen sulfide (H 2 S) is an endogenous gaseous biological mediator. In the cardiovascular system, it acts as a vasodilator, proangiogenic hormone, and cardioprotectant, while in the nervous system, it functions as a neurotransmitter and neuroprotectant. Our interest in the role of H 2 S in cancer biology was initially triggered by our observations in endothelial cells showing that the proang...

Hydrogen sulfide (H2S) is enzymatically generated in mammalian tissues from either L-cysteine or L-homocysteine. H2S possesses multiple biological activities, including regulation of vascular tone and blood pressure. Hydrogen sulfide produced in endothelial cells, vascular smooth muscle cells, and perivascular adipose tissue dilates blood vessels by activating ATP-sensitive potassium channels. ...

Endogenous hydrogen sulfide (H2S) is naturally synthesized in many types of mammalian cells from L-cysteine in the reactions catalyzed by cystathionine-β-synthase (CBS) and cystathionine-γlyase (CSE). H2S has been demonstrated to play a pro-inflammatory role in various animal models of hind paw edema, acute pancreatitis, lipopolysaccharide (LPS)-induced endotoxemia, and cecal ligation and punct...

The reduction of the triple bond and carbonyl group of an , ketoalkyne, 4-phenyl-3-butyn-2-one (PBYO), by rat liver microsomes and cytosol was investigated. The triple-bond-reduced product trans-4-phenyl-3-buten-2-one (PBO) and the carbonyl-reduced product 4-phenyl-3-butyn-2-ol (PBYOL) were formed when PBYO was incubated with rat liver microsomes in the presence of NADPH. The triple bond of 1-p...