Structure and Kinetic Analysis of H2S Production by Human Mercaptopyruvate Sulfurtransferase

Abstract

Background: Mercaptopyruvate sulfurtransferase (MST) generates H 2 S, a signaling molecule. Results: The detailed kinetics and crystal structure of human MST with bound substrate are reported. Conclusion: Thioredoxin is the preferred persulfide acceptor from MST. Significance: The structure provides molecular insights into activation and stabilization of MST reaction intermediates.

Sulfide Oxidation by a Noncanonical Pathway in Red Blood Cells Generates Thiosulfate and Polysulfides

“…At the desired time points, 200-l aliquots were collected from the gas phase and injected into a gas chromatograph equipped with a model 355 sulfur chemiluminescence detector (Agilent) for H 2 S analysis as described (25). The reaction mixture contained 10 mM cysteine for CSE activity (26), 10 mM cysteine ϩ 10 mM D,Lhomocysteine for CBS activity (26), and 0.5 mM 3-mercaptopyruvate ϩ 20 mM DTT to monitor MST activity (23).…”

“…The following reagents were obtained from the indicated vendors: monobromobimane (FluoroPure grade, Molecular Probes, Grand Island, NY), 3-mercaptopyruvate (Research Organics, Cleveland, OH), and DTT (Gold Biotechnology, St. Louis, MO). Recombinant human CBS (20,21), CSE (22,23), MST (23), and methionine synthase reductase (MSR) (24) were purified as described previously.…”

NO• Binds Human Cystathionine β-Synthase Quickly and Tightly

“…CBS and cystathionine ␥-lyase are considered the prominent enzymatic sources of H 2 S, their distribution, abundance, and contribution to H 2 S synthesis appearing to be tissue-specific (1,5,6). Recent studies on 3-mercaptopyruvate sulfurtransferase contributed to reevaluate its physiological relevance in H 2 S generation (7).…”

Characterization and Interaction Studies of Two Isoforms of the Dual Localized 3-Mercaptopyruvate Sulfurtransferase TUM1 from Humans

“…Human TUM1 shares about 60% amino acid sequence identity to MPST homologues from various sources. The crystal structure of human and yeast TUM1, also in complex with 3-MP has been solved at 2.15-Å resolution (13,14). TUM1 is expressed in kidney cells, liver cells, cardiac cells, and neurological cells (15).…”