Tris-type buffers are known to inhibit a number of enzymes of the GH classes, including dextransucrase and starch synthases. The attached papers may give you some leads to other work.

Thank you Greg Cote. So if I understand there is no confirmed direct inhibitory effect of Tris-type buffers on alpha-amylase activity but just on dextransucrase and starch synthases..

I don't know about amylases - someone may have done that in the past. I only know about the foregoing work by Robyt.

Also, tris is known to inhibit intestinal glucosidases: Dahlqvist, Biochem J. 80:547 (1961) and Kelemen & Whelan, Arch Biochem Biophys 117:423 (1966). Many people working in the field assume it is inhibitory toward all enzymes of this class.

OK, thanks a lot!