2,4-Dichlorophenoxyacetic acid had a multiple effect on the development of indoleacetic acid oxidase isoenzymes in tobacco callus tissues (Nicotiana tabacum, cv. White Gold) cultured in vitro, and the development of these isoenzymes was differentially associated with growth promotion or inhibition depending on the concentration of 2,4-dichlorophenoxyacetic acid. At low concentrations (0.1 to 1 ...

We studied the response of each ascorbate peroxidase (APX) isoenzyme in spinach leaves under stress conditions imposed by high light intensity, drought, salinity, and applications of methyl viologen and abscisic acid. The steady-state transcript level of cytosolic APX remarkably increased in response to high-light stress and methyl viologen treatment, but not in response to the other stress tre...

After preincubation of human lactate dehydrogenase (EC 1.1.1.27) isoenzymes 1 through 5 with lactate at pH 9.4, 9.8, 10.25, and 10.6 at 30 degrees C for 10 min, the reduction of NAD+ was measured at the same pH values and temperature during the interval 1-2 min after adding the coenzyme. Relative to the reference activities measured at pH 8.7 by the method of Buhl et al. (Clin Chem 23: 1289-129...

Two isoforms of fructose 1,6-bisphosphatase are present in the green alga Selenastrum minutum. The isoenzymes can be separated with ionexchange chromatography or acid precipitation. The stability of the two isoenzymes differ largely. The acid insoluble enzyme exhibits properties similar to that of the enzyme from the chloroplasts of higher plants, i.e. an alkaline pH optima in the absence of re...

Two isoenzymes of NADP-linked isocitrate dehydrogenase have been identified in Acinetobacter lwoffi and have been termed isoenzyme-I and isoenzyme-II. The isoenzymes may be separated by ion-exchange chromatography on DEAE-cellulose, by gel filtration on Sephadex G-200, or by zonal ultracentrifugation in a sucrose gradient. Low concentrations of glyoxylate or pyruvate effect considerable stimula...

The enzyme 5α-reductase, which converts testosterone to dihydrotestosterone (DHT), performs key functions in the androgen receptor (AR) signaling pathway. The three isoenzymes of 5α-reductase identified to date are encoded by different genes: SRD5A1, SRD5A2, and SRD5A3. In this study, we investigated mechanisms underlying androgen regulation of 5α-reductase isoenzyme expression in human prostat...

We read with a great pleasure the article ‘Rare ADH variant constellations are specific for alcohol dependence’ by Zuo et al. (2012). We want to direct the speciality about the alcohol dehydrogenase (ADH) isoenzyme nomenclature to the readers of Alcohol and Alcoholism. Namely, the authors use an old isoenzyme nomenclature what can cause some confusion to not enough familiar readers. Electrophor...

Three isoenzymes of yeast phosphoglucose isomerase were studied by physical and chemical methods to establish their subunit properties and to identify the structural differences among them which give rise to their heterogeneous chromatographic behavior. Equilibrium sedimentation ultracentrifugation in 6 M guanidine hydrochloride and polyacrylamide gel electrophoresis in the presence of sodium d...

The isoenzyme pattern of LDH does not play a physiological role; except perhaps during fast transitions in energy metabolism. Aging, 3(5), 457-460. Introduction: A paper describing increased brain lactate concentration with age recently caught our attension [1]. The proposed explanation for the increased brain lactate with age was a shift in the brain lactate dehydrogenase (LDH) isoenzyme patte...

Both in vivo and in vitro experiments on wild-type Escherichia coli K-12 and mutant strains possessing only single 3-deoxy-d-arabino-heptulosonic 7-phosphate acid (DAHP) synthetase isoenzymes indicated that, under conditions when all three isoenzymes are fully repressed, sufficient chorismate is still formed for the synthesis of aromatic vitamins. Under repressed conditions both DAHP synthetase...