Document Detail

Biosynthetic mechanism of 2-acetyl-1-pyrroline and its relationship with Delta1-pyrroline-5-carboxylic acid and methylglyoxal in aromatic rice (Oryza sativa L.) callus.
MedLine Citation:
PMID:  18680302     Owner:  NLM     Status:  MEDLINE    
2-Acetyl-1-pyrroline (2-AP) was identified as the major flavor compound in aromatic rice varieties Tainung 71 and 72. In order to understand the mechanism of 2-AP biosynthesis in aromatic rice, we studied the formation of putative precursors, Delta(1)-pyrroline-5-carboxylic acid and methylglyoxal. The endogenous Delta(1)-pyrroline-5-carboxylic acid contents of Tainung 71 and 72 calli reached 191 to 276%, compared to nonaromatic rice Tainung 67. In addition, calli of Tainung 71 and 72 contained 1.30- and 1.36-fold, respectively, higher methylglyoxal levels than that of Tainung 67. Specific enzyme activities of Delta(1)-pyrroline-5-carboxylic acid-synthetic enzyme including Delta(1)-pyrolline-5-carboxylic acid synthetase (P5CS) and ornithine aminotransferase (OAT) increased significantly in aromatic rice varieties. The expression levels of P5CS1 and P5CS2 genes were found to be significantly higher in aromatic rice than nonaromatic rice. Results of a tracer experiment with (15)N-labeled glutamic acid revealed that the nitrogen atom of 2-acetyl-1-pyrroline was derived from glutamic acid. Upregulation of P5CS in aromatic rice Tainung 72 may contribute to the increase of Delta(1)-pyrroline-5-carboxylic acid level and thus leads to the accumulation of an extra amount of 2-acetyl-1-pyrroline.
Tzou-Chi Huang; Chia-Shih Teng; Jia-Lin Chang; Hui-Su Chuang; Chi-Tang Ho; Mei-Li Wu
Publication Detail:
Type:  Journal Article; Research Support, Non-U.S. Gov't     Date:  2008-08-05
Journal Detail:
Title:  Journal of agricultural and food chemistry     Volume:  56     ISSN:  1520-5118     ISO Abbreviation:  J. Agric. Food Chem.     Publication Date:  2008 Aug 
Date Detail:
Created Date:  2008-08-21     Completed Date:  2008-10-06     Revised Date:  -    
Medline Journal Info:
Nlm Unique ID:  0374755     Medline TA:  J Agric Food Chem     Country:  United States    
Other Details:
Languages:  eng     Pagination:  7399-404     Citation Subset:  IM    
Department of Food Science, National Pingtung University of Science & Technology, 912, Pingtung, Taiwan.
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MeSH Terms
Odors / analysis*
Oryza sativa / chemistry*,  enzymology
Pyrroles / analysis,  metabolism*
Pyruvaldehyde / analysis,  metabolism*
Seeds / chemistry
Reg. No./Substance:
0/2-acetyl-1-pyrroline; 0/Pyrroles; 2906-39-0/delta-1-pyrroline-5-carboxylate; 78-98-8/Pyruvaldehyde

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