Mass spectrometry (MS)-based enzyme assay has been shown to be a useful tool for screening enzymatic activities from environmental samples. Recently, reported approaches for high-specificity multiplexed characterization of enzymatic activities allow for providing detailed information on the range of enzymatic products and monitoring multiple enzymatic reactions. However, the throughput has been...

Immobilized enzymatic reactors recently have drawn much attention because of the striking advantages, such as high substrate turnover rate and ease in coupling with the separation and detection systems. Carrier materials, which have great effects on the development of the immobilized enzymatic reactors, have always being the focus of study. In this paper, the contributions, mainly in the last 5...

All chemical transformations pass through an unstable structure called the transition state, which is poised between the chemical structures of the substrates and products. The transition states for chemical reactions are proposed to have lifetimes near 10(-13) sec, the time for a single bond vibration. No physical or spectroscopic method is available to directly observe the structure of the tr...

lated bacteriophages f2 and MS2. Personal communications from W. Konigsberg and H. FraenkelConrat. 4Goldthwait, D. A., and G. R. Greenberg, in Methods in Enzymology, ed. S. P. Colowick and N. 0. Kaplan (New York: Academic Press, 1955), vol. 2, p. 516. 6 Rabinowitz, J. C., in The Enzymes, ed. P. D. Boyer, H. Lardy, and K. Myrback (New York: Academic Press, 1960), vol. 2, p. 185. 6lHuennekens, F....

A NEW FIELD in enzymology has emerged in the past decade with the discovery that RNA can act as an enzyme. First discovered in the cellular RNA-splicing and processing machinery in the form of self-splicing group 1 introns’ and precursor tRNA-processing RNase P (Ref. 2) RNA catalytic activity in a number of smaller RNAs has subsequently been identified3-5. The small, naturally occurring catalyt...

We evaluated a new analyzer that measures lactate in undiluted whole blood by direct (or undiluted) amperometry [Nova Stat Profile 7 Analyzer (SP7); Nova Biomedical, Waltham, MA] by comparing it with two other analyzers, one for measuring lactate in whole blood by indirect (or diluted) amperometry [Model 2300; Yellow Springs Instrument Co. (YSI), Yellow Springs, OH] and another for measuring la...

This article describes the design, synthesis and characterization of an optical sensor suitable for practical measurement of ionized calcium in serum and whole blood samples. The key to the development of this sensor is the identification of a chemically very stable, nitrogen-containing, calcium selective ionophore, coupled with a fluorophore having the correct spectral and electron accepting p...

The most common procedure in searching for active sites in biological macromolecules is partial hydrolysis. In a few cases, acidic, alkaline, or enzymatic breakdown of the macromolecule results in the removal of the inert sites of the complex, reducing the size of the remainder to the active core structure. Similar treatments frequently serve as steps of purification by removing noncovalently b...

Beaufay, H., Bendall, D. S., Baudhuin, P., Wattiaux, R. & de Duve, C. (1959). Biochem. J. 73, 628. Beinert, H. (1957). In Manometric Techniqute, p. 146. Ed. by Umbreit, W. W., Bums, R. H. & Stauffer, J. F. Minneapolis: Burgess Publishing Co. Conchie, J. & Levvy, G. A. (1960). Biochem. J. 74, 12P. de Duve, C., Pressman, B. C., Gianetto, R., Wattiaux, R. & Appelmans, F. (1955). Biochem. J. 60, 60...

An emerging paradigm in enzymology is that transient high-energy structural states play crucial roles in enzymatic reaction cycles. Generally, these high-energy or 'invisible' states cannot be studied directly at atomic resolution using existing structural and spectroscopic techniques owing to their low populations or short residence times. Here we report the direct NMR-based detection of the m...