Direct ring fission of salicylate by a salicylate 1,2-dioxygenase activity from Pseudaminobacter salicylatoxidans.

In cell extracts of Pseudaminobacter salicylatoxidans strain BN12, an enzymatic activity was detected which converted salicylate in an oxygen-dependent but NAD(P)H-independent reaction to a product with an absorbance maximum at 283 nm. This metabolite was isolated, purified, and identified by mass spectrometry and (1)H and (13)C nuclear magnetic resonance spectroscopy as 2-oxohepta-3,5-dienedioic acid. This metabolite could be formed only by direct ring fission of salicylate by a 1,2-dioxygenase reaction. Cell extracts from P. salicylatoxidans also oxidized 5-aminosalicylate, 3-, 4-, and 5-chlorosalicylate, 3-, 4-, and 5-methylsalicylate, 3- and 5-hydroxysalicylate (gentisate), and 1-hydroxy-2-naphthoate. The dioxygenase was purified and shown to consist of four identical subunits with a molecular weight of about 45,000. The purified enzyme showed higher catalytic constants with gentisate or 1-hydroxy-2-naphthoate than with salicylate. It was therefore concluded that P. salicylatoxidans synthesized a gentisate 1,2-dioxygenase with an extraordinary substrate range, which also allowed the oxidation of salicylate.

[Behavior of alkaline serum phosphatase (AP) and its bone isoenzyme in healing of the osteotomized tibia in rabbits--an animal experimental study]. / Verhalten der alkalischen Serumphosphatase (AP) und ihres Knochenisoenzyms bei der Heilung an der osteotomierten Kaninchentibia--eine tierexperimentelle Studie.

The effectiveness of the electrical stimulation on the healing of an osteotomy was proved by determining the total alkaline phosphatase (AP) in the serum and its bone isoenzyme in rabbits. A non-stimulated animal group served as control. The changes appeared more distinctly by interference stimulation than by stimulation with bipolar rectangle impulses.