Ketopantoate Formation by a Hydroxymethylation Enzyme From Escherichia Coli

Structure elucidation of the teicoplanin antibiotics

“…'6, in ppm; J, in Hz. 4 Abbreviations used: s = singlet, nc = not comparable, "Data obtained at 60 °C. 6ppm/(K X 103).…”

“…Recent work has shown that teicoplanin's major component (T-A2) consists of five major factors, designated T-A2-1 to T-A2-5, and small amounts of other compounds. 4 Our studies have been confined to determining the structures of the above five major factors of the T-A2 complex. In practice this has involved determining also the structures of simpler compounds, obtained by partial hydrolysis of the T-A2 complex. We have used a combination of *H and 13C NMR, fast atom bombardment mass spectrometry (FAB MS), chemical degradations, and gas chromatography-mass spectrometry (GCMS) to elucidate the structures.…”

Biosynthesis of pantothenate

“…The condensation of a-ketoisovalerate with formaldehyde to give ketopantoate had been demonstrated chemically in 1942 27 but the corresponding enzymatic activity, ketopantoate hydroxymethyl transferase (KPHMT) was not detected until 1957. 35 This activity was stimulated by the addition of divalent metal ions and to some extent by the addition of tetrahydrofolate. This finding was supported by earlier data that p-aminobenzoic acid (PABA) was involved in pantothenate metabolism [36][37][38] and suggested a mechanism analogous to that reported for serine hydroxymethyltransferase.…”

“…As will be described in the following sections, the four enzymes from this organism have now all been overexpressed, purified and characterised and their crystal structures have been obtained. 35 As a first step, they carried out a heat denaturation of other proteins at 95 • C for one minute, since KPHMT activity was observed to remain in the soluble fraction. The same workers also demonstrated activity in crude lysates of Acetobacter suboxydans, Corynebacterium creatinovorans, and Lactobacillus arabinosus.…”

“…In 1957 McIntosh et al 35 measured formation of ketopantoate in extracts from E. coli in the absence of tetrahydrofolate. They found an immeasurably high K M for a-KIVA of over 100 mM.…”