A combination of selective spin decoupling, two-dimensional double quantum spectroscopy, correlated spectroscopy (COSY), and pH titration experiments brought about the assignment of all tyrosyl spin systems and completed the assignment of the histidyl spin systems in porcine adenylate kinase. In the detection of the tyrosyl spin systems it proved to be advantageous to resort to the COSY method ...

Ammonium sulfate fractionated proteins of bitter gourd (Momordica charantia) were precipitated using jack bean extract as a source of concanavalin A. Concanavalin A-bitter gourd peroxidase retained nearly 86% original activity. This complex was entrapped into calcium alginate-pectin gel. Entrapped concanavalin A-peroxidase complex retained 51% original activity. Soluble and immobilized peroxida...

The protein CcdB (controller of cell division or death B) is an F-plasmid-encoded toxin that acts as an inhibitor of Escherichia coli DNA gyrase. The stability and aggregation state of CcdB have been characterized as a function of pH and temperature. Size-exclusion chromatography revealed that the protein is a dimer at pH 7.0, but a monomer at pH 4.0. CD analysis and fluorescence spectroscopy s...

The onset of hen egg white lysozyme aggregation on exposure to alkaline pH of 12.2 and subsequent slow growth of soluble lysozyme aggregates (at 298 K) was directly monitored by steady-state and time-resolved fluorescence anisotropy of covalently attached dansyl probe over a period of 24 h. The rotational correlation time accounting for tumbling of lysozyme in solution (40 microM) increased fro...

the thermal denaturation of α-amylase from bacillus amyloliquefaciens has been investigated in the presence and absence of sodium dodecyl sulphate (sds) over the temperature range (293-373) k in 20 mm sodium phosphate buffer, ph 6.9, using temperature scanning spectroscopy. the presence of sds caused the destabilization of α-amylase resulting in a decrease in the temperature of unfolding with a...

We introduce a simplified protein model where the solvent (water) degrees of freedom appear explicitly (although in an extremely simplified fashion). Using this model we are able to recover the thermodynamic phenomenology of proteins over a wide range of temperatures. In particular we describe both the warm and the cold protein denaturation within a single framework, while addressing important ...

The antiulcer and in vitro anti-inflammatory activities of the aerial parts of Enicostemma littorale against aspirin, ethanol, and pyloric ligation-induced ulcers in rats and bovine serum albumin denaturation were studied. The extract (200 mg/kg and 400 mg/kg po) was administered to the overnight fasted rats, one hour prior to aspirin / alcohol / pyloric ligation challenge. The ulcer index, tis...

Using cytidine 2':3' cyclic monophosphate as a substrate, Km and k(cat) of ribonuclease-A in the presence of different concentrations of D-amino acids (Ala, Ser, Pro and Lys) and their L-isomers were measured at pH 6.0 and 25 degrees C. These kinetic parameters remained unchanged in the presence and absence of D-and L-amino acids. This is the first experimental evidence showing that D-amino aci...

To study the antimalarial action of chloroquine, normal mouse erythrocytes were used as surrogates for erythrocytoid bodies. These bodies form in the endosomes of intraerythrocytic malaria parasites as they feed on their host and consist of erythrocyte cytoplasm enclosed in a vestige of the erythrocyte membrane. In suspensions of normal erythrocytes or lysates (equivalent to 5 microl of erythro...

Thermal denaturation of RNA free coat proteins of tobacco mosaic virus (TMV) was studied for wildtype TMV (vulgare) and the temperature-sensitive mutant, Ni 118. The ability to form soluble aggregates as well as the optical properties (ORD, UV-difference spectra), and the sedimen­ tation behavior were used as criteria for the native state. At pH 7.5 , 7 = 0 .0 2 denaturation is reversible for b...