Looking for decarboxylase

HAYASHI YASUNORI yhayashi-tky at umin.u-tokyo.ac.jp
Thu Jan 16 20:57:54 EST 1997

Pierre AUBINEAU wrote:
> I'm presently designing a new research protocol which supposes that I can
> visualize histologically (L.S. confoc. microsc., or electron mic.) the
> cellular localization of the first step of serotonin sythesis, i.e., 5-HTP.
> Since, to my knowledge, no Ab exist against 5-HTP, the easiest way seems to
> me to transform ex-vivo the 5-HTP into 5-HT by the action of a L-amino acid
> decarboxylase. Could tyrosine decarboxylase be efficient for this purpose ?
> Does it exist a more specific decarboxylase available (commercially or
> not).

Hi, Pierre

As far as I know, "tyrosine decarboxylase" is identical with "5-HTP decarboxylas
e" thus now collectively called L-amino acid decarboxylase (AADC). There are som
e papers which purify this enzyme from pig kidney.  It is stable and I don't thi
nk it is so difficult to purify.  Even partical purification might be enough for
 your purpose as inhibitors (NSD1015 etc) are available.  But I wonder why you w
ant to do like that.  If you use AADC you will have 5-HT but how do you discrimi
nate it with endogenous 5-HT?  What about using antibody against tryptophan hydr
oxylase?  Also under usual condition, very little 5-HTP are detected compared wi
th 5-HT because while tryptophan hydroxylase is rate limitting and rather weak e
nzyme, AADC is very strong enzyme.

Hope this helps.

Yasunori Hayashi

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