Under conditions where cytochalasin B induces ATPase activity of monomeric actin (0.3 mM MgCl2, 1 mM EGTA, 30 microns cytochalasin B, 1 mM ATP) the rate constant of the exchange of actin-bound epsilon-ATP for free ATP is about 4-6 times faster than steady state ATPase activity. When a stoichiometric ATP-actin complex is extracted with PCA (single turnover experiment) the apparent rate constant ...

Secretory phospholipase A(2) (sPLA(2)) is an interesting enzyme for triggered liposomal drug delivery to tumor tissue due the overexpression of sPLA(2) in cancerous tissue. A drug delivery system based on the triggered release of therapeutics from sPLA(2)-sensitive liposomes constituted of pro anticancer ether lipids, which become cytotoxic upon sPLA(2)-catalyzed hydrolysis has previously been ...

The kinetics of cellulose hydrolysis under extremely low acid (ELA) conditions (0.07 wt%) and at temperatures >200°C was investigated using batch reactors and bed-shrinking flow-through (BSFT) reactors. The maximum yield of glucose obtained from batch reactor experiments was about 60% for α-cellulose, which occurred at 205 and 220°C. The maximum glucose yields from yellow poplar feedstocks were...

Vertebrate myosin Va is a typical processive motor with high duty ratio. Recent studies have revealed that the actin-activated ATPase activity of the full-length myosin Va (M5aFull) is inhibited at a low [Ca(2+)], which is due to the formation of a folded conformation of M5aFull. To clarify the underlying inhibitory mechanism, we analyzed the actin-activated ATP hydrolysis mechanism of the M5aF...

Although proteins consist exclusively of L-amino acids, we have reported that aspartyl (Asp) 58 and Asp 151 residues of αA-crystallin of eye lenses from elderly cataract donors are highly inverted and isomerized to D-β, D-α and L-β-Asp residues through succinimide intermediates. Of these Asp isomers, large amounts of D-β- and L-β-isomers are present but the amount of D-α-isomer is not significa...

The hydrolysis of small unilamellar vesicles made of dipalmitoylphosphatidylcoline by pancreatic phospholipase A2 has been studied under various conditions of temperature and enzyme and substrate concentration using the following three different experimental protocols. When the enzyme was added to the substrate vesicles after being separately adjusted to the temperature of the experiments hydro...

−− A previously developed deterministic steady state module for modeling methanogenic biofilm reactors has been revised to enlarge the model application range and to deal with system dynamics. Two models for the hydrolysis of non-active biomass representing extreme alternatives: without biomass hydrolysis (model A) and with complete and instantaneous hydrolysis of non-active suspended and attac...

A partially purified preparation of an alpha-amino acid ester hydrolase was obtained from Acetobacter turbidans A.T.C.C. 9325, which catalyses synthesis of 7-(d-alpha-amino-alpha-phenylacetamido)-3-cephem-3-methyl-4- carboxylic acid (cephalexin) from methyl d-alpha-aminophenylacetate and 7-amino-3-deacetoxycephalosporanic acid. The enzyme preparation catalysed both cephalosprin synthesis from 7...

A continuous-culture device, adapted for use with solid substrates, was used to evaluate the effects of 3-phenylpropanoic acid (PPA) upon the ability of the South African strain Ruminococcus albus Ce63 to ferment cellulose. Steady states of fermentation were established with a dilution rate of 0.17 h, and the extent and volumetric rates of cellulose fermentation were determined over four consec...

The kinetics of ATP binding and hydrolysis (formation of acid-labile phosphate) by the Tetrahymena 30 S dynein ATPase has been measured by chemical quench flow methods. The amplitude of the ATP-binding transient gave a molecular weight per ATP-binding site of approximately 750,000, suggesting nearly 3 ATP binding sites12 million M, dynein molecule (Johnson, K. A., and Wall, J. S . (1983) J. ...