Publications

• A rapid purification procedure and computer-assisted sulfide ion selective electrode assay for O-acetylserine sulfhydrylase from Salmonella typhimurium.

  Hara S., Payne M.A., Schnackerz K.D., Cook P.F.

  An improved method for purifying O-acetylserine sulfhydrylase from Salmonella typhimurium is described as well as a new computer-controlled assay making use of the sulfide ion selective electrode. The purification method uses gradient elution from Q-Sepharose Fast Flow and phenyl-Sepharose columns ... >> More

  An improved method for purifying O-acetylserine sulfhydrylase from Salmonella typhimurium is described as well as a new computer-controlled assay making use of the sulfide ion selective electrode. The purification method uses gradient elution from Q-Sepharose Fast Flow and phenyl-Sepharose columns to give 75 mg (50% yield) of the enzyme starting from 300 g of starting material in 3 days. The sulfide electrode assay makes use of sulfide and calomel electrodes attached to a signal buffer which serves as an impedance match. The output of the signal buffer is linked in parallel to a strip chart recorder and a Keithley Model 575 data acquisition and control system. The system 575 is interfaced to a Packard-Bell AT computer. In addition, two BASIC computer programs have been written to convert potential measured by the electrode to sulfide concentration and to convert the time course data to rates. << Less

  Protein Expr Purif 1:70-76(1990) [PubMed] [EuropePMC]

• Role of pyridoxal 5'-phosphate in the structural stabilization of O-acetylserine sulfhydrylase.

  Bettati S., Benci S., Campanini B., Raboni S., Chirico G., Beretta S., Schnackerz K.D., Hazlett T.L., Gratton E., Mozzarelli A.

  Proteins belonging to the superfamily of pyridoxal 5'-phosphate-dependent enzymes are currently classified into three functional groups and five distinct structural fold types. The variation within this enzyme group creates an ideal system to investigate the relationships among amino acid sequence ... >> More

  Proteins belonging to the superfamily of pyridoxal 5'-phosphate-dependent enzymes are currently classified into three functional groups and five distinct structural fold types. The variation within this enzyme group creates an ideal system to investigate the relationships among amino acid sequences, folding pathways, and enzymatic functions. The number of known three-dimensional structures of pyridoxal 5'-phosphate-dependent enzymes is rapidly increasing, but only for relatively few have the folding mechanisms been characterized in detail. The dimeric O-acetylserine sulfhydrylase from Salmonella typhimurium belongs to the beta-family and fold type II group. Here we report the guanidine hydrochloride-induced unfolding of the apo- and holoprotein, investigated using a variety of spectroscopic techniques. Data from absorption, fluorescence, circular dichroism, (31)P nuclear magnetic resonance, time-resolved fluorescence anisotropy, and photon correlation spectroscopy indicate that the O-acetylserine sulfhydrylase undergoes extensive disruption of native secondary and tertiary structure before monomerization. Also, we have observed that the holo-O-acetylserine sulfhydrylase exhibits a greater conformational stability than the apoenzyme form. The data are discussed in light of the fact that the role of the coenzyme in structural stabilization varies among the pyridoxal 5'-phosphate-dependent enzymes and does not seem to be linked to the particular enzyme fold type. << Less

  J Biol Chem 275:40244-40251(2000) [PubMed] [EuropePMC]

• The purification and characterization of O-acetylserine sulfhydrylase-A from Salmonella typhimurium.

  Becker M.A., Kredich N.M., Tomkins G.M.

  J Biol Chem 244:2418-2427(1969) [PubMed] [EuropePMC]