scholarly journals Non-metabolizable amino acids are potent stimulators of hepatic and renal ornithine decarboxylase activity

1983 ◽  
Vol 210 (2) ◽  
pp. 617-619 ◽  
Author(s):  
E W Chideckel ◽  
D Edwards
Keyword(s):  
Amino Acids ◽  
Amino Acid ◽  
Ornithine Decarboxylase ◽  
Decarboxylase Activity ◽  
Protein Meal ◽  
Aminoisobutyric Acid ◽  
Ornithine Decarboxylase Activity

The non-metabolizable amino acids alpha-aminoisobutyric acid (AIB) and cycloleucine and the poorly metabolizable amino acid D-alanine potently stimulated hepatic ornithine decarboxylase (ODC) activity in starved rats. The stimulation by AIB was shown to have several of the characteristics of stimulation by a protein meal and occurred in hypophysectomized animals. AIB also stimulated renal, but not brain or heart, ODC activity.

scholarly journals Phenotypic and Genotypic Analysis of Amino Acid Auxotrophy in Lactobacillus helveticus CNRZ 32

2007 ◽  
Vol 74 (2) ◽  
pp. 416-423 ◽  
Author(s):  
Jason K. Christiansen ◽  
Joanne E. Hughes ◽  
Dennis L. Welker ◽  
Beatriz T. Rodríguez ◽  
James L. Steele ◽  
...  
Keyword(s):  
Amino Acids ◽  
Lactic Acid ◽  
Amino Acid ◽  
Lactic Acid Bacteria ◽  
Ornithine Decarboxylase ◽  
Lactobacillus Helveticus ◽  
Decarboxylase Activity ◽  
Biosynthetic Pathways ◽  
Ornithine Decarboxylase Activity ◽  
Genotypic Analysis

ABSTRACT The conversion of amino acids into volatile and nonvolatile compounds by lactic acid bacteria in cheese is thought to represent the rate-limiting step in the development of mature flavor and aroma. Because amino acid breakdown by microbes often entails the reversible action of enzymes involved in biosynthetic pathways, our group investigated the genetics of amino acid biosynthesis in Lactobacillus helveticus CNRZ 32, a commercial cheese flavor adjunct that reduces bitterness and intensifies flavor notes. Most lactic acid bacteria are auxotrophic for several amino acids, and L. helveticus CNRZ 32 requires 14 amino acids. The reconstruction of amino acid biosynthetic pathways from a draft-quality genome sequence for L. helveticus CNRZ 32 revealed that amino acid auxotrophy in this species was due primarily to gene absence rather than point mutations, insertions, or small deletions, with good agreement between gene content and phenotypic amino acid requirements. One exception involved the phenotypic requirement for Asp (or Asn), which genome predictions suggested could be alleviated by citrate catabolism. This prediction was confirmed by the growth of L. helveticus CNRZ 32 after the addition of citrate to a chemically defined medium that lacked Asp and Asn. Genome analysis also predicted that L. helveticus CNRZ 32 possessed ornithine decarboxylase activity and would therefore catalyze the conversion of ornithine to putrescine, a volatile biogenic amine. However, experiments to confirm ornithine decarboxylase activity in L. helveticus CNRZ 32 by the use of several methods were unsuccessful, which indicated that this bacterium likely does not contribute to putrescine production in cheese.

Stimulation of rat ovarian ornithine decarboxylase in vitro by hCG, amino acids and bovine serum albumin

1980 ◽  
Vol 94 (4) ◽  
pp. 571-576 ◽  
Author(s):  
Kirsti Käpyaho
Keyword(s):  
Amino Acids ◽  
Bovine Serum Albumin ◽  
Cyclic Amp ◽  
Serum Albumin ◽  
Ornithine Decarboxylase ◽  
Bovine Serum ◽  
Defined Medium ◽  
Decarboxylase Activity ◽  
Ornithine Decarboxylase Activity

Abstract. Rat ovarian ornithine decarboxylase activity could be stimulated in vitro by a variety of factors, which apparently have different modes of action. Ovarian cells prepared from pre-pubertal rats by collagenase dispersion exhibited a low but detectable ornithine decarboxylase activity after a 6-h incubation in a defined medium. The enzyme activity was markedly enhanced in vitro by hCG, which also produced increased accumulation of cyclic AMP and stimulated the secretion of progesterone. In addition to the gonadotrophin, ovarian ornithine decarboxylase activity was strikingly stimulated by some non-essential amino acids, and especially by bovine serum albumin. While markedly enhancing ornithine decarboxylase activity, none of the latter additions increased the accumulation of cyclic AMP or enhanced the secretion of progesterone. Bovine serum albumin enhanced powerfully ornithine decarboxylase activity in vitro at very small concentrations (from 0.75 μm). The half-life of the enzyme remained unchanged (26—28 min) upon stimulation indicating that the stimulation mechanism did not involve any stabilization of the enzyme.

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