Joseph V. Bannister

The superoxide dismutase activity of human erythrocuprein

The supe~oxide dismutase activity of bovine erythzocuprein ~as usual]y b~en deI~rmined by a xelafi=,ely complex procedu_~e in which the prote~n corn pet~s wi~h cytoeh,mme c or nitr~Mue ~etrazoliurn for the superoxide ,anion (O~) produced either enzyrnatieally I1--9] or phmoch~mieally 1 tl3] ~n ]ow concentrations. Recently, however, the leehrdque o f pulse radioly~is has been used for the assay [ l 1,12.1] as i~ is a convenient me thod of producing, virtually instantane 0usly, large concentrations ,of O~ I 1 3 i 5]. Th~ turnover of lhe sabstrate can then be followed directly ~asing the absozp~on baud o f 0~, which has an ex~.ncgon ¢,oef~Nen~ o f 2000 ~¢I a ~-m a ax 245 n~n. In tlgs paper we w i ~ to describe some o f ,the phyNc~ and chemic~d characteristics of the ~ p e r o x i d e d~smu~tse activity o f huznan e ry th ro~pre in as eta.died by pulse radi~ly~i~.

Isolation and characterization of iron superoxide dismutase from Bacillus megaterium

Abstract 1. 1. The iron Superoxide dismutase (E.C. 1.15.1.1) of Bacillus megaterium has been isolated. The enzyme had a mol. wt of approx 40,000 and appeared to consist of 2 non-covalently linked subunits. Iron was present as l g atom per mole of enzyme. A small amount (about 0.2 g atom) of tightly bound copper was also found. A virtually iron-free apoprotein was prepared. The amino acid composition of the enzyme was quite similar to that of other bacterial iron Superoxide dismutases. 2. 2. The state of the tryptophan and tyrosine residues was investigated. The holoprotein showed the fluorescence characteristics of tryptophan in a hydrophobic environment. About 7 tyrosine residues were titratable at alkaline pH. This was half the number of tyrosines found by amino acid analysis. The number of titratable tyrosines increased to 11 in 6 M guanidine-HCl. One tyrosine and 5 tryptophan residues appeared to undergo exposure to the solvent at acid pH. The protein appeared to maintain some rigid core under denaturing conditions. 3. 3. Absorption and circular dichroism (CD) spectra are presented. The far u.v. CD indicated about 50% helical and about 10% β-sheet secondary structure.

Cytosol superoxide dismutase from swordfish (Xiphias gladius L.) liver

Abstract 1. 1. Copper-zinc or cytosol superoxide dismutase was isolated from swordfish ( Xiphias gladius L.) liver. The dissociation of the enzyme into subunits, its amino acid composition, and its absorption, fluorescence and circular dichroism (CD) spectra were determined. 2. 2. The superoxide dismutase has a higher content of arginine and tyrosine than the corresponding bovine enzyme and appears to dissociate more readily into subunits. It resembles the bovine enzyme in secondary structure as determined from far ultraviolet CD spectra.

The effect of fructose 1,6-diphosphate on pyruvate kinase from white muscle of three species of Mediterranean fish

Abstract 1. 1. The kinetics of pyruvate kinase in the absence and presence of fructose 1,6-diphosphate was investigated in preparations from white muscle of Boops boops (L.), Coryphaena hippurus (L.) and Mugil cephalus (L.). 2. 2. Mugil cephalus pyruvate kinase showed sigmoidal kinetics which changed to hyperbolic in the presence of fructose 1,6-diphosphate with increase in substrate affinity and maximum velocity. 3. 3. Coryphaena hippurus and Boops boops pyruvate kinase showed hyperbolic kinetics with increase in substrate affinity and maximum velocity in the presence of fructose 1,6-diphosphate, but the Boops boops enzyme was inhibited in the presence of the effector at phosphoenolpyruvate concentrations above 0.375 mM.

Purification of an N-acetylglucosaminidase from the limpet Patella vulgata (L.)

N-Acetylglucosaminidases are useful tools for the study of the structure of glycolipids, glycoproteins and polysaccharides. /3-N-Acetylglucosaminidase (EC 3.2.1.30) has been partially purified from various sources and has been characterised electrophoretically from jack bean meal [ 11, Aspergillus oryzae [2], Staphylococcus aureus [3], hen oviduct [4], beef spleen [5] and Bacillus subtilis [6]. a-N-Acetylglucosaminidase has been partially purified only from pig liver [7] and Turbo cornutus liver [8] . In this paper we describe the purification to a state of apparent homogeneity of an N-acetylglucosaminidase from the digestive gland of the limpet Patella vulgata (L.) which hydrolyses both the (Yand fl-glycosides of N-acetylglucosamine. Limpet digestive gland had previously been noted to possess (Yand /3-N-acetylglucosaminidase activity [9] .

Least squares estimation of Michaelis—Menten parameters by a fibonacci search method

Since the parameter KM occurs nonlinearly in the Michaelis-Menten equation, the normal eqs. (2a) and (2b) are nonlinear in this parameter. It is standard practice to bypass nonlinear normal equations [ 11. In fitting the Michaelis-Menten equation the recommended procedure has been to fit iteratively the approximation to the equation obtained by taking the linear part of a Taylor series expansion about KM [2,3]. This requires starting values for KM and V. We propose here an alternative optimization procedure which does not depend on the provision of initial estimates of the Michaelis-Menten parameters. The method takes advantage of the fact that the sum of

Oxygen and carbon monoxide binding to myoglobin from the dolphin fish Coryphaena hippurus

Complete quantitative studies are necessary to attempt any correlation between molecular structure and functional properties in simple, non-cooperative hemoproteins from various sources. One of the purposes of these studies is to clarify the structural factors which control the reactivity of the heme towards various ligands. In this communication we report a complete characterization of the equilibrium and kinetics of 02 and CO binding to the myoglobin from the dolphin fish, Coryphaena hippurus, recently purified by Bannister and Bannister [ 1 ]. This work seemed of interest from a comparative standpoint, since no kinetic information on fish myoglobin is as yet available.

Kinetic properties of N-acetylglucosaminidases from the limpet patella vulgata (L.)

Abstract 1. 1. Patella vulgata has been found to possess an N -acetylglucosaminidase capable of hydrolysing both α- and β-acetylglucosaminidase and a β - N -acetylglucosaminidase. 2. 2. The two β - N -acetylglucosaminidase activities have essentially the same kinetic behaviour. 3. 3. The results obtained also suggest that active sites of the α- and β - N -acetylglucosaminidase in the α,β-enzyme are not independent.