An aminotransferase from Lactococcus lactis initiates conversion of amino acids to cheese flavor compounds

The enzymatic degradation of amino acids in cheese is believed to generate aroma compounds and therefore to be involved in the complex process of cheese flavor development. In lactococci, transamination is the first step in the degradation of aromatic and branched-chain amino acids which are precurs...

Full description

Saved in:
Bibliographic Details
Published in:Applied and Environmental Microbiology 1997-02, Vol.63 (2), p.414-419
Main Authors: Yvon, M. (I.N.R.A., Jouy-en-Josas, France.), Thirouin, S, Rijnen, L, Fromentier, D, Gripon, J.C
Format: Article
Language:English
Subjects:
ACIDE AMINE
Amino acids
Amino Acids - metabolism
AMINOACIDOS
AMINOTRANSFERASAS
AMINOTRANSFERASE
Bacteria
Bacteriology
Biological and medical sciences
Biology of microorganisms of confirmed or potential industrial interest
Biotechnology
Cheese
Cheese - microbiology
COMPOSE DE LA FLAVEUR
COMPUESTOS DEL SABOR
Ecology, environment
Enzymes
Flavoring Agents - metabolism
Food industries
FROMAGE
Fundamental and applied biological sciences. Psychology
LACTOCOCCUS LACTIS
Lactococcus lactis - enzymology
Lactococcus lactis cremoris
Life Sciences
Metabolism. Enzymes
Microbiology
Milk and cheese industries. Ice creams
Mission oriented research
Phenylalanine - metabolism
Physiology and metabolism
QUESO
Substrate Specificity
Transaminases - isolation & purification
Transaminases - metabolism
Citations: Items that cite this one
Online Access:Get full text
Tags: Add Tag
No Tags, Be the first to tag this record!
Description
Summary:The enzymatic degradation of amino acids in cheese is believed to generate aroma compounds and therefore to be involved in the complex process of cheese flavor development. In lactococci, transamination is the first step in the degradation of aromatic and branched-chain amino acids which are precursors of aroma compounds. Here, the major aromatic amino acid aminotransferase of a Lactococcus lactis subsp. cremoris strain was purified and characterized. The enzyme transaminates the aromatic amino acids, leucine, and methionine. It uses the ketoacids corresponding to these amino acids and alpha-ketoglutarate as amino group acceptors. In contrast to most bacterial aromatic aminotransferases, it does not act on aspartate and does not use oxaloacetate as second substrate. It is essential for the transformation of aromatic amino acids to flavor compounds. It is a pyridoxal 5'-phosphate-dependent enzyme and is composed of two identical subunits of 43.5 kDa. The activity of the enzyme is optimal between pH 6.5 and 8 and between 35 and 45 degrees C, but it is still active under cheese-ripening conditions
ISSN:0099-2240
1098-5336
DOI:10.1128/aem.63.2.414-419.1997