What was hydroxy-lysine?

[Brian T. Greuel]

In article <2ojups$o2l at mercury.hgmp.mrc.ac.uk>, mlush at crc.ac.uk (Mr. M.J. 
Lush) writes:

> We have managed to produce a limited amount of protein 
> sequence by edman degredation,  unfortunatly one of these contains two 
> hydroxy-lysines.  
> 
> 	We wish to use these protein sequences to devise degenerate 
> oligos so we want to know:- 
> 
> 	What was hydroxy-lysine (OH-lys) before it was altered? 


It was lysine!  Lysine and proline residues are hydroxylated in some proteins 
by a specific hydroxylase enzyme which occurs in the endoplasmic reticulum.  
These modifications are made co-translationally, I believe, to produce 
hydroxylysine and hydroxyproline residues, respectively.

> 
> 	Is this an artifact?

Of what?  The Edman degradation?  I don't think so.

 
> 	Has OH-lys been found in proteins _other_ than collagen? 
> And if so what was it doing there?

It is also found in elastin, another extracellular matrix protein.  I think 
these hydroxylysine and hydroxyproline residues act to stabilize the 
interchain linkages of fibrous proteins such as collagen and elastin.

> -- 
> Michael


Hope this helps.

‹ Brian