3,α^4-Di-O-dioctanoyl pyridoxine was transformed into α^4-N-octanoyl pyridoxamine by reacting with ammonia at 60℃ for 3 hours. This conversion also occurred with α^4,α^5-Di-O-dioctanoyl pyridoxine and 5-O-octanoyl pyridoxine at the same condition. α^4-N-Octanoyl pyridoxamine was also synthesized by reaction of pyridoxamine HCl with caprylyl chloride. α^4-N-octanoyl pyridoxamine obtained by the two methods agreed in mp, IR and thin layer chromatography. α^4-N-acetyl pyridoxamine and α^4-N-lauroyl pyridoxamime were synthesized in the same manner. Solubilities of α^4-O-octanoyl pyridoxine and α^4-N-octanoyl pyridoxamine in organic solvents and their spectronic properties were measured. Effect of boric acid on the colouration of pyridoxamine derivatives with a 2,6 -dibro-moquinonechloroimide was studied. Hydrolysis of α^4-N-octanoyl pyridoxa mine by acid, alkali and enzymes was also investigated.

抄録全体を表示

A derivative of pyridoxal 5'-phosphate (PALP) bund to Sepharose 4B through the OH-group at position 3 of PALP was prepared by reacting PALP with bromoacetamidohexyl-Sepharose at pH 6.5. A Sepharose-bound tryptophan-PALP complex was also derived from the Sepharose-bound PALP by reducing the Schiff base between Sepharose-bound PALP and tryptophan with NaBH_4. These Sepharose-bound derivatives of PALP were found to be very useful as bio-specific adsorbents for apo-tryptophanase : Apo-tryptophanase adsorbed on a column of Sepharose -bound PALP was eluted specifically with a mixture of potassium phosphate buffer (0.5M, pH 7.0) and PALP (1mM), thus being purified 8〜10 times; much more specific elution of apotryptophanase adsorbed on a column of Sepharose-bound tryptophan-PALP comp1ex was observed. The apoprotein was eluted only with a mixture of PALP, tryptophan and potassium phosphate buffer, being much more efficiently purified by the affinity chromatography on the column.

抄録全体を表示

The transport of ^3H-pyridoxal (^3H-PAL) across the intestinal wall was studied with the everted sacs of rat small intestine, mainly at an initial ^3H-PAL concentration of 0.3μM on the mucosal side. The serosal concentration of labelled compounds continuously increased, but did not reach the mucosal level during 4-hour incubation at 37℃, and the time course apparently subjected to first-order kinetics during the first 2 hours of incubation. Addition of 300μM 4-deoxypyridoxine or 10-fold increase of initial mucosal ^3H-PAL concentration did not significantly affect the time course of the ratio of serosal to mucosal concentration, but affected the extent of ^3H-PAL uptake by the tissue. The transport at 0℃ was much slower than that at 37℃ and apparently subjected to first order kinetics for 4 hours. Comparison of the rate constants with those of pyridoxine showed that PAL was transported faster than pyridoxine either at 37℃ or 0℃. Analysis of the serosal ^3H-compounds after 2-hour incubation with 0.3 or 3μM ^3H-PAL by column chromatography on Dowex 50W indicated that almost of them was ^3H-PAL.

抄録全体を表示

The transport of ^3H-pyridoxamine (^3H-PAM) from the mucosal to serosal side of everted sacs was examined mainly at an initial mucosal ^3H-PAM concentration of 0.3μM, at 37℃ for 4 hours. The serosal concentration of ^3H-compounds never reached the mucosal level, and the time course of the ratio of serosal to mucosal concentration was not significantly affected by the addition of 300μM 4-deoxypyridoxine (DOPIN) or 10-fold increase of initial ^3H-PAM concentration. The transport was remarkably depressed by lowering the temperature to 0℃. Comparison of the three forms of vitamin B_6 with respect to the rate of transport gave the following order : pyridoxal (PAL)>PAM>pyridoxine (PIN), which was different from the order of uptake rate by the tissue. The main component of the serosal ^3H-compounds after 2-hour transport was ^3H-PAM, but the presence of ^3H-PAL was also significant. For comparison the serosal fluid after incubation of everted sacs with 0.3μM ^3H-PIN was examined, and was found to contain much more ^3H-PAL than the case of ^3H-PAM transport. Its relative amount diminished by the addition of phosphate buffer or DOPIN, or by 10-fold increase of the initial mucosal concentration of ^3H-PIN.

抄録全体を表示