I recently encountered a picture (taken by Acris antibodies) demonstrating amylase 2b in brain tissue. It surprised me since it is an enzyme produced by pancreas. Does anyone know if this amylase or other amylases such as AMY1a and AMY2a can be present in the brain?
According to human transcriptome database, amylase 2B does show up in brain:
http://h-invitational.jp/h-dbas/locusOverview.do?dbname=human_mrna&hix=HIX0021182
Like you, I too was under the impression that amylase transcripts are expressed only in pancreas and salivary gland - which are still the two predominant locations.
It seems when one searches carefully using sensitive tools, compared to commonly held views, there are many excursions of tissue specificities at least at transcriptional level and occasionally on translational levels.
Generally we do not think of brain as an organ which stores glycogen like liver or muscle but some cells do... so why not amylase! ;)
Vopr Med Khim. 1977 Jan-Feb;(1):105-9.
[Acid gamma-amylase of rabbit and human brain].
Popova IA, Akopian AS.
Abstract
Preparations of acidic gamma-amylase, which cleaved glycogen and maltose, were isolated from human and rabbit brain tissues. The specific activity of the gamma-amylase preparations from human brain was approximately twice higher than the activity of the enzyme from rabbit brain. In degradation of glycogen gamma-amylases from human and rabbit brain had the pH optima at pH 4.9 and 4.6 and with maltose as a substrate- at pH 4.3 and 4.1, respectively. gamma-Amylases from both sources possessed the high stability in presence of monovalent cations. K+ distinctly increased the cleavage of glycogen by gamma-amylase from human and rabbit brain. alpha, alpha-Trehalose and alpha-menthyl glucoside proved to be inhibitors of the glucoamylase activity of the enzymes from both sources. Km values of the gamma-amylases for glycogen were equal to 19.3 mM 19.8 and for maltose -5.54 mM and 5.78 mM, respectively. The data obtained suggest that acidic gamma-amylases from human and rabbit brain are similar to acidic gamma-amylases from other sources.
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