Inulosucrases catalyze transfer of a fructose moiety from sucrose to a water molecule (hydrolysis) or to an acceptor molecule (transferase), yielding inulin. Bacterial inulin production is rare and a biochemical analysis of inulosucrase enzymes has not been reported. Here we report biochemical characteristics of a purified recombinant inulosucrase enzyme from Lactobacillus reuteri. It displayed...

It is not always clear that some equations affected by complicated factors can, actually, be interpreted as a ratio of two polynomials of first degree and so that they can be, in general, represented by rectangular hyperbolas. In this paper we present an easy procedure to rearrange those equations into Michaelis-Menten-type equations and so to make the aspects of these rectangular hyperbolas mo...

Single-cell RNA sequencing is able to quantify the whole transcriptome from the small amount of RNA present in individual cells. However, a consequence of reverse-transcribing and amplifying small quantities of RNA is a large number of dropouts, genes with zero expression in particular cells. The frequency of dropout events is strongly non-linearly related to the measured expression levels of t...

ER aminopeptidase 1 (ERAP1) customizes antigenic peptide precursors for MHC class I presentation and edits the antigenic peptide repertoire. Coding single nucleotide polymorphisms (SNPs) in ERAP1 were recently linked with predisposition to autoimmune disease, suggesting a link between pathogenesis of autoimmunity and ERAP1-mediated Ag processing. To investigate this possibility, we analyzed the...

Real time monitoring of electrolyte resistance changes during hydrolysis of 4-nitrophenylphosphate (pNPP) by alkaline phosphatase (ALP) bound on paramagnetic-beads was performed into a small dielectric channel. The reaction kinetic fit with a non-competitive substrate-inhibition equation. Michaelis-Menten apparent constant, KM(app), was determined as 0.33±0.06mM and the maximum apparent rate, V...

Enzyme hydrolysis kinetic model of inulin by inulinase from Kluyveromyces lactis was established. The corresponding Michaelis-Menten equation model constants were found to be related to temperature through the Arrhenius model. The kinetic model was validated by experimental data and also be utilized to predict the hydrolysis reaction rates of the inulin for substrate concentrations ranging betw...

The statistical implications of the direct linear plot for enzyme kinetic data, described in the preceding paper (Eisenthal & Cornish-Bowden, 1974), are discussed for the case of the Michaelis-Menten equation. The plot is shown to lead directly to non-parametric confidence limits for the kinetic parameters, V and K(m), which depend on far less sweeping assumptions about the nature of experiment...

The site specific endonuclease Bam HI which is composed of subunits of a molecular weight of 22 000 [1] can aggregate to complexes of a molecular weight of 360 000. It is an acidic protein with an isoelectric point at pH 5.3. Optimal activity is reached at 13 mM MgCl2. A very simple method is presented to determine kinetic constants of restriction enzymes directly from agarose gel photographs w...

The electric charges on an enzyme may move concomitantly with a conformational change. Such an enzyme will absorb energy from an oscillating electric field. If in addition the enzyme has a larger association constant for substrate than for product, as is often true, it can use this energy to drive the catalyzed reaction away from equilibrium. Approximate analytical expressions are given for the...

Whole metabolizing Brevibacterium linens cells were used to study the transport of aromatic amino acids. Kinetic results followed the Michaelis-Menten equation with apparent Km values for phenylalanine, tyrosine, and tryptophan of 24, 3.5, and 1.8 microM. Transport of these amino acids was optimum at pH 7.5 and 25 degrees C for phenylalanine and pH 8.0 and 35 degrees C for tyrosine and tryptoph...