BRANCHING GLYCOSYLTRANSFERASE FROM

FAO/WHO Expert Consultation on Allergenicity of Foods Derived from Biotech-
nology. A 35% homology within a sliding window of 80 amino acids to 
Į-amylase
from Aspergillus oryzae was identified. Aspergillus oryzae is recognized as the
occupational allergen Asp o 21 and was also reported to cause allergy symptoms
in a few individuals after ingestion. However, no homology between branching
glycosyltransferase and 
Į-amylase from A. oryzae was found at the level of six
contiguous amino acid sequences. In addition, branching glycosyltransferase is a
bacterial protein, whereas nearly all known allergens are of eukaryotic origin. Thus,
branching glycosyltransferase does not seem to have the characteristics of a
potential food allergen.
4.2
Toxicological data
Toxicological studies were performed with branching glycosyltransferase
using a representative batch (PPY 27209), which was produced according to the
procedure used for commercial production. The liquid enzyme preparation used in
the toxicological studies was a mixture of three preparations from fermentation sub-
batches. The final preparation (specific gravity 1.065 g/ml) had an activity of 89 200
BEU/g and a TOS value of 7.3%.
In a 13-week study of general toxicity in rats, no toxicologically relevant
effects were seen when branching glycosyltransferase was administered daily by
gavage at doses up to 769 mg TOS/kg bw per day. This dose, the highest dose
tested, was therefore taken to be the NOAEL.
Branching glycosyltransferase was not mutagenic in an assay for muta-
genicity in bacteria in vitro and was not clastogenic in an assay for chromosomal
aberrations in human lymphocytes in vitro.

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