The isoenzymes of aspartate transaminase differ in their kinetic properties in that the cytoplasmic isoenzyme is more readily inhibited by adipate and by 2-oxoglutarate (substrate) at low pH. A differential kinetic assay based on this phenomenon has been optimised for use in assays of serum samples. The new method agrees well with an immune absorption procedure. Methods based on chromatographic...

-. 1 3 . Miernyk. J. A. & Dennis. I>. 1 ( 1982) I’lurit I’hyxiol. 69. 825-828 Journet. E. P. & Douce. R. ( 1 984) (‘. K. Acud. Sci. /’(iris Ser. 111 298, 365-370 Hotha, F. C. & Dennis, D. R. ( 1986) Arch. Bioc,hem. Bioplrvs. 245.96I03 Fothergill. L. A. & Harkins. R. N . ( 1982) /’roc.. K. Soc. London H215, 19-44 White. M. F. & Fothergill-Gilmore. L. A. (1988) FEES Lett. 229,383-387 Winn. S. I.,...

Human isoenzyme LDH-X (lactate dehydrogenase isoenzyme X) was isolated from seminal fluid of frozen semen samples by affinity chromatography by using oxamate-Sepharose and AMP-Sepharose. In the presence of 1.6 mM-NAD+, isoenzyme LDH-X does not bind to AMP-Sepharose, whereas the other lactate dehydrogenase isoenzymes do. This is the crucial point in the isolation of isoenzyme LDH-X from the othe...

The pelB gene, which encodes one of the five pectate lyase isoenzymes of Erwinia chrysanthemi 3937, was mutagenized with a mini-Mu transposable element that can form gene fusions to the neomycin phosphotransferase-encoding region. Secondary mutants resistant to kanamycin in the absence of polygalacturonate, an inducer of wild-type pectate lyase activities, were selected. Such mutants produced o...

The enzyme acetohydroxy acid synthase (AHS), which catalyses the first common step in the biosynthesis of isoleucine, leucine and valine, has been demonstrated to be present in Spirufinupfutensis in two isoenzymic forms. The complete nucleotide sequences of the genes ifuX and ifu W encoding these two enzymes have been determined. Sequence analysis revealed the presence of two open reading frame...

The ALP activities and properties of rat intestine cut into 20 segments were examined, and we were able to demonstrate that the ALP activity of upper intestine is high compared to that of lower intestine. This result coincided with those of other reports. However, we newly clarified that there is an ALP isoenzyme found in the lower intestine which can be inhibited by L-homoarginine. The molecul...