Developing a highly efficient 4-hydroxyphenylacetate-3-hydroxylase for salvianic acid A synthesis by computer-aided molecular modification.

Salvianic acid A (SAA) is a catechol compound known for its diverse physiochemical functions and has significant applications in the food and pharmaceutical industries. 4-Hydroxyphenylacetate-3-hydroxylase (4HPA3H) is a critical enzyme for SAA biosynthesis, and improving its activity towards p-hydroxyphenyllactate acid (4HPLA) is essential for highly efficient SAA production in stable biosynthetic pathways. To address this, the distal site and loops of the substrate pocket were modified to improve 4HPA3H catalytic activity towards 4HPLA using computer-aided molecular modification methods.

[Effect of atropine on the inhibition of melatonin to the unit discharges evoked in the posterior group of thalamic nuclei in cats].

Aim: To study the effect of atropine, muscarinic cholinergic antagonist, on the central analgesic action of melatonin (MT) and to explore the mechanism of MT analgesia.

Methods: As an indicator of visceral pain, the unit discharges of the neurons in the posterior group of thalamic nuclei (PO) were caused by stimulating the great splanchnic nerve (GSN) of the cat. The cranial stereotaxic and extracellular glass microelectrode record technique were used.