Amylolytic activity of IgG and sIgA immunoglobulins from human milk.
BACKGROUND
New natural amylolytic abzymes (Abs) for catalytically active antibodies from human milk have been identified and investigated.


METHODS
The amylolytic activity of human milk autoantibodies was studied by TLC and HPLC techniques analyzing the hydrolysis of maltooligosaccharides with different degrees of polymerization and of 4-nitrophenyl 4,6-O-ethylidene-alpha-D-maltoheptaoside (EPS). IgG and sIgA fractions were isolated from human milk by affinity chromatography. After SDS-PAGE preparation of native IgG and sIgA and their renaturation, the amylolytic activity was in-gel assayed.


RESULTS
All electrophoretically homogeneous preparations of IgG and its Fab fragments as well as sIgA antibodies possessed alpha-amylolytic activity. The specific activities of these catalytic antibodies varied in the range from 1.83 up to 3.33 kat/kg, which is about one order of magnitude higher than that for IgGs from the sera of cancer patients. IgG and sIgA fractions showed Michaelis constants for hydrolysis of 4-nitrophenyl 4,6-O-ethylidene-alpha-D-maltoheptaoside in the range of 10(-4) M/l. Fractions of autoantibodies from different donors exhibited different modes of action in hydrolysis of maltooligosaccharides, maltose and p-nitrophenyl-alpha-D-glucopyranose.


CONCLUSIONS
IgG antibodies, their Fab fragments, and sIgA fractions isolated from human milk of healthy women possessed amylolytic activity in the hydrolysis of maltooligosaccharides and several artificial substrates.
Savel'ev
A N
AN
Biophysics Department, St. Petersburg Technical University, St. Petersburg, Russia.
Kanyshkova
T G
TG
Kulminskaya
A A
AA
Buneva
V N
VN
Eneyskaya
E V
EV
Filatov
M V
MV
Nevinsky
G A
GA
Neustroev
K N
KN
D000328:Adult; D000681:Amylases / Q000032:analysis / Q000378:metabolism; D000682:Amyloid / Q000378:metabolism*; D002855:Chromatography, Thin Layer; D004591:Electrophoresis, Polyacrylamide Gel; D005260:Female; D005959:Glucosidases / Q000378:metabolism; D006801:Humans; D006868:Hydrolysis; D015151:Immunoblotting; D007071:Immunoglobulin A, Secretory / Q000302:isolation & purification / Q000494:pharmacology*; D007140:Immunoglobulin Fab Fragments / Q000737:chemistry / Q000302:isolation & purification; D007074:Immunoglobulin G / Q000302:isolation & purification / Q000494:pharmacology*; D007202:Indicators and Reagents; D007700:Kinetics; D008320:Maltose / Q000737:chemistry; D008895:Milk, Human / Q000201:enzymology* / Q000276:immunology*; D009844:Oligosaccharides / Q000378:metabolism; D013379:Substrate Specificity
D000682:Amyloid; D007071:Immunoglobulin A, Secretory; D007140:Immunoglobulin Fab Fragments; D007074:Immunoglobulin G; D007202:Indicators and Reagents; D009844:Oligosaccharides; D008320:Maltose; D000681:Amylases; D005959:Glucosidases