In many biological research efforts, long chain organic molecules are studied by breaking large molecules into smaller components. Cleavage technique of recent interest is the use of solvated electrons. These are formed when aqueous solutions are bombarded with gamma radiation. Solvated electron is very reactive and can reduce most any species present, even to form free radicals

Garrison, W. M.

Holian, J.

English

NASA Technical Reports Server

June 1973
	
	
B7340194 
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AEC-NASA Tech Briefs announce new technology derived from the research and development program of the U.S. AEC 
or from AEC-NASA interagency efforts. They are issued to encourage commercial application. Tech Briefs are available 
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Reductive Cleavage of the Peptide Bond 
In many biological research efforts, long chain organic 
molecules are studied by breaking the large molecules 
into smaller components. One method of doing this is 
reductive cleavage of the peptide (amid) bond in mole-
cules such as RCONHR to give an amine, NH 2 R, and a 
Variety of carbonyl products such as (RCO)2 and RCHO. 
A cleavage technique that has been of recent interest 
is the use of solvated electrons, eaq These are formed 
when aqueous solutions are bombarded with gamma 
radiation. The solvated electron is very reactive and can 
reduce most any species present, even to form free 
radicals. 
.	 One of the reactions which will occur in a gamma-ray 
bombarded aqueous solution of peptides is 
eThq + RCONHR + 11 2 0 - RC(OH)NR + OH—
The peptide may also be attacked by OH and H radicals 
in the solution. The peptide free radicals combine with 
reductive cleavage of the amide linkage: 
2 RC(OH)NHR _+ R(CO)2 +2 NH2R 
However, the yield of carbonyl products from this and 
other reactiojis occurring in the system is very small. 
This is thought to result from a preferential, competing, 
recombination reaction among the peptide free radicals. 
It has been found that this back reaction may be 
blocked by the addition of certain labile organic corn-
pounds, especially thiols, RSH. The blocking occurs by 
virtue of the hydrogen atom transfer reaction: 
RC(OH)NHR + RSH -+RCHC(OH)NHR + RS 
which in turn leads to reductive cleavage of the amide 
linkage: 
RCH(OH)NHR - RCHO + NH2R 
In this case the aldehyde appears as the major product. 
The thiol effectively blocks the back reaction. 
Note: 
Requests for further information may be directed to: 
Technology Utilization Officer 
Lawrence Berkeley Laboratory 
University of California 
Berkeley, California 94270 
Reference: B7310194 
Patent status: 
NASA has decided not to apply for a patent. 
Source: John Holian and
Warren M. Garrison

Lawrence Berkeley Laboratory 
(LRL- 10026) 
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Reductive cleavage of the peptide bond

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