The structure of 'metal-free' glucose isomerase of Streptomyces albus strain number YT ATCC 21132 has been analysed and refined at 1.65 A. The space group is I222, with cell dimensions a = 93.9 (1), b = 99.7 (1) and c = 102.9 (1) A, and there is one monomer of the tetrameric molecule per asymmetric unit. The data were recorded from two crystals of the protein using synchrotron radiation from th...

Glucose isomerase (GI) (D-xylose ketol-isomerase; EC. 5.3.1.5) catalyzes the reversible isomerization of D-glucose and D-xylose to D-fructose and D-xylulose, respectively. The enzyme has the largest market in the food industry because of its application in the production of high-fructose corn syrup (HFCS). HFCS, an equilibrium mixture of glucose and fructose, is 1.3 times sweeter than sucrose a...

1. Methods of homogenizing suspensions of washed mammalian spermatozoa were studied. The most useful methods were those using sonication and those using a French press. 2. Hexokinase, phosphofructokinase, glucose phosphate isomerase and adenosine triphosphatase activities in ram, bull and boar spermatozoa were investigated by using these two homogenization methods. Glucose phosphate isomerase, ...

The electrostatic potential of an enzyme is a key determinant of its substrate interactions and catalytic turnover. Here we invoke comparative analysis of protein electrostatic potentials, along with sequence and structural analysis, to classify and characterize all the enzymes in an entire pathway across a set of different organisms. The electrostatic potentials of the enzymes from the glycoly...

Streptomyces sp. US 24 and Streptomyces sp. TN 58, two strains producing interesting bioactive molecules, were successfully transformed using E. coli ET12567 (pUZ8002), as a conjugal donor, carrying the integrative plasmid pSET152. For the Streptomyces sp. US 24 strain, two copies of this plasmid were tandemly integrated in the chromosome, whereas for Streptomyces sp. TN 58, the integration was...

Glucose-6-phosphate isomerase (phosphoglucose isomerase [PGI]) (EC 5.3.1.9) from the hyperthermophilic archaeon Pyrococcus furiosus was purified 500-fold to homogeneity. The enzyme had an apparent molecular mass of 43 kDa and was composed of a single type of subunit of 23 kDa indicating a homodimeric (alpha(2)) structure. Kinetic constants of the enzyme were determined at the optimal pH 7 and a...

A partially purified D-xylose isomerase has been isolated from cells of Streptomyces albus NRRL 5778 and some of its properties have been determined. D-Glucose, D-xylose, D-ribose, L-arabinose, and L-rhamnose served as substrates for the enzyme with respective Km values of 86, 93, 350, 153, and 312 mM and Vmax values measuring 1.23, 2.9, 2.63, 0.153, and 0.048 mumol min per mg of protein. The h...

Axenic cultures of Suillus bovinus were cultivated in inorganic liquid medium with glucose as a carbon source at 25 degrees C and continuous supply of oxygen by aeration with compressed air in the dark. Exogenous fructose as sole carbon source yielded about 50% less increase in dry weight than glucose. This resulted from different uptake velocities. Sucrose as sole exogenous carbon source yield...

Aim: To characterize, TK1111, a cupin-type phosphoglucose isomerase from a hyperthermophilic archaeon Thermococcus kodakarensis. Methods: The genome of T. kodakarensis was searched in order to find an open reading frame annotated as glucose-6-phosphate isomerase. The structural gene was cloned, expressed in Escherichia coli and the purified gene product was characterized. Effect of metal ions o...

A simple, rapid colorimetric method for the estimation of phosphoglucose isomerase activity, using the determination of fructose by the method of Roe, Epstein, and Goldstein (1949), is described. An arbitrary fructose standard is advocated and normal values for human serum and cerebrospinal fluid are presented.