HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH TABLE OF CONTENTS		QUICK SEARCH:   [advanced] Author: Keyword(s): Year:  Vol:  Page:

This Article Full Text (PDF) Alert me when this article is cited Alert me if a correction is posted Services Email this article to a friend Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via HighWire Citing Articles via Google Scholar Google Scholar Articles by Rahmanian, M. Articles by Smith, W. G. Search for Related Content PubMed PubMed Citation Articles by Rahmanian, M. Articles by Smith, W. G. Social Bookmarking                      What's this?

Biosynthesis of d-Aspartic Acid by Streptococcus faecalis

From the ¹ From the Departments of Biochemistry, University of Arkansas School of Medicine, Little Rock, Arkansas 72201, and Oklahoma State University, Stillwater, Oklahoma 74074

In biotin deficiency, aspartic acid becomes a limiting factor in the growth of Streptococcus faecalis ATCC 9790. Suboptimal concentrations of l-aspartate in biotin-deficient medium produce partial growth followed by lysis, which is typical of cell wall lysis due to depletion of an amino acid essential for cell wall biosynthesis. d-Aspartate, which is utilized by the cells with considerable less efficiency than the l isomer, can prevent depletion lysis when present at high concentrations. Irrespective of aspartate concentration, a minimal concentration of biotin is so indispensable for normal growth that at lower biotin concentrations partial growth occurs followed by cell lysis.

l-Aspartate-¹⁴C included in the growth medium is incorporated into d-aspartate isolated from the cell wall. Dilution with endogenously synthesized amino acid is a function of aspartate and biotin concentrations. Wall and protein aspartic acids were isolated from cells grown with dl-aspartate-1-¹⁴C or with dl-aspartate-4-¹⁴C and selectively decarboxylated with chloramine-T in alkali to locate the position of ¹⁴C in the molecule. Lack of randomization of ¹⁴C between the - and ß-carboxyl groups indicated the absence of a symmetrical intermediate with enzymically indistinguishable carboxyl groups (fumarate) in the pathway between l- and d-aspartic acid.

Cell wall d-aspartate isolated from cells grown on l-aspartate-¹⁵N contained nearly the same ¹⁵N content as the l-aspartate in the medium, indicating that d-aspartate is formed from l-aspartate via racemization.

CiteULike    Complore    Connotea    Del.icio.us    Digg    Reddit    Technorati    What's this?

This article has been cited by other articles:

				Z. Cokesa, H.-J. Knackmuss, and P.-G. Rieger Biodegradation of All Stereoisomers of the EDTA Substitute Iminodisuccinate by Agrobacterium tumefaciens BY6 Requires an Epimerase and a Stereoselective C-N Lyase Appl. Envir. Microbiol., July 1, 2004; 70(7): 3941 - 3947. [Abstract] [Full Text] [PDF]