Dear Muhammad,

If the nitrogen in pyridine bonded with metal on the surface of the catalyst, so this is a Lewis acidic sites, however, if it bonded with the hydrogen in OH group, this is Bronsted site (as seen in the photo attached)

In case the surface group of the catalyst has M-O-H group so it will form both lewis and Bronsted acidic sites  

please find the attached paper that discussed this

hope this helping 

Thanks

Ahmed