Tyrosine sulphate

Bob Lauder bsa016 at cent1.lancs.ac.uk
Tue Jan 11 07:11:11 EST 1994

Hi there, 

 I'm looking at a (glyco)protein which has some of its tyrosine residues
sulphated.  I'm interested in assaying the levels of tyrosine sulphation
in the protein isolated from different sources.  Main problem is that the
sulphate is acid labile and all the tyrosine sulphate is lost to plain old
tyrosine during acid hydrolysis.

 I tried the method of Christie et al 1986 - base hydrolysis with Ba(OH)2
which is neutralised with H2SO4 to form insoluble BaSO4.  The authors reckon
they could get 43% recovery of tyrosine sulphate.  Unfortunalty I got almost 
none when I tried this out on either my protein, or, on purified tyrosine 

 So I'd love to hear from you if you have experience of amino acid analysis of 
acid labile groups, especially of tyrosine sulphate. Also if you have any ideas
what could be used to bring about base hydrolysis and is volatile.


Bob Lauder,				bsa016 at cent1.lancs.ac.uk
Post Doctoral Research Associate,	
Division of Biological Sciences,	VOICE - (+44) (0)524 65201 Ex 3461
Lancaster University,			FAX   - (+44) (0)524 843854

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