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| Predicate | Object |
|---|---|
| rdf:type | |
| lifeskim:mentions | |
| pubmed:issue |
21
|
| pubmed:dateCreated |
1992-11-27
|
| pubmed:abstractText |
A superpotent analog of human growth hormone-releasing factor, [desNH2Tyr1,D-Ala2,Ala15]-GRF(1-29)-NH2 (4), was prepared from the precursor, [Ala15,29]-GRF(4-29)-OH (1), by a two-step enzymatic semisynthesis. The amidated C-terminus, essential for high biological potency, was obtained via a carboxypeptidase Y-catalyzed exchange of Ala29-OH for Arg29-NH2 to produce [Ala15]-GRF(4-29)-NH2 (2). The N-terminal desNH2Tyr-D-Ala moiety, which greatly increases in vivo duration of action, was then incorporated by V8 protease-catalyzed condensation of segment 2 with desNH2Tyr-D-Ala-Asp(OH)-OR [R = CH3CH2- (3a) or 4-NO2C6H4CH2-(3b)]. The main focus of this report was to develop conditions to use the V8 protease-catalyzed coupling while avoiding a competing cleavage of the proteolytically-sensitive Asp25-Ile26 bond in GRF. Conversion of 2 to 4 in couplings employing the alpha-ethyl ester of the acyl component 3a was limited to about 60% by competing proteolysis at Asp25-Ile26. This system was adequate for preparing, isolating, and fully characterizing the target analog 4 and identifying the side products. The 4-nitrobenzyl ester 3b proved to be a superior substrate, resulting in 90% conversion of 2 to 4 with no detectable loss to proteolysis and requiring significantly lesser amounts of catalyst. These results demonstrate that enzymatic semisynthesis of a biologically-active peptide amide which contains unnatural amino acids at the N-terminus can be achieved from a biosynthetic precursor in good yield and purity.
|
| pubmed:language |
eng
|
| pubmed:journal | |
| pubmed:citationSubset |
IM
|
| pubmed:chemical | |
| pubmed:status |
MEDLINE
|
| pubmed:month |
Oct
|
| pubmed:issn |
0022-2623
|
| pubmed:author | |
| pubmed:issnType |
Print
|
| pubmed:day |
16
|
| pubmed:volume |
35
|
| pubmed:owner |
NLM
|
| pubmed:authorsComplete |
Y
|
| pubmed:pagination |
3934-41
|
| pubmed:dateRevised |
2006-11-15
|
| pubmed:meshHeading |
pubmed-meshheading:1433202-Amino Acid Sequence,
pubmed-meshheading:1433202-Chromatography, High Pressure Liquid,
pubmed-meshheading:1433202-Humans,
pubmed-meshheading:1433202-Hydrogen-Ion Concentration,
pubmed-meshheading:1433202-Molecular Sequence Data,
pubmed-meshheading:1433202-Peptide Fragments,
pubmed-meshheading:1433202-Serine Endopeptidases,
pubmed-meshheading:1433202-Sermorelin
|
| pubmed:year |
1992
|
| pubmed:articleTitle |
Enzymatic semisynthesis of a superpotent analog of human growth hormone-releasing factor.
|
| pubmed:affiliation |
Department of Peptide Research, Roche Research Center, Hoffmann-La Roche Inc., Nutley, New Jersey 07110.
|
| pubmed:publicationType |
Journal Article
|