The nervus acusticus. VI.—Vestibular symptomatology

Synthesis and biological properties of new hexapeptide substrates for vitamin K dependent carboxylase. Evidence for X-Pro cis/trans amide bond interconversions in prothrombin precursor fragment 18-23

“…carboxylation also affects the conversion of glutamyl to -y-carboxyglutamyl. This finding is most clearly illustrated by comparing sequences 5-9 (1) and [18][19][20][21][22][23] (3), both of which contain the segment Leu-Glu-Glu; peptide 1 is efficiently carboxylated,10 while the cyclic disulfide peptides 3a,b are partial substrates-inhibitors of the carboxylase.13 Furthermore, Soute et al14 reported that segment 13-29 of prothrombin precursor (4) is efficiently carboxylated at 1000-fold lower concentrations (Km 1 µ ) than segments 18-23 (3a,b) or 24-29 (5),15 as well as segment 5-9 (1) (Km = 8 mmol), implying that some favorable structural (12) Biochim. Biophys.…”

“…or conformational features are present in segment [13][14][15][16][17][18][19][20][21][22][23][24][25][26][27][28][29] that are not present in the smaller segments.…”

“…Analogues to Prothrombin Sequence[18][19][20][21][22][23] A. Substrate Activity at Varying Concentrations…”

“…n-Butyraldoxime and other oximes are about as effective as pyrazole in rats,18 but in man the oxime induced a reaction like that with disulfiram, in which blood acetaldehyde levels increased after ingestion of ethanol. 19 n-Butyramide is almost as effective as pyrazole in blocking ethanol oxidation in rats and is less toxic.18 Thus, it is worthwhile to test other carboxamides to find potent, nontoxic inhibitors of alcohol dehydrogenase.…”