Lysozyme is present in various body fluids and change in
the lysozyme content in these fluids is indicative of
certain disease states (Jolles and Jolles, 1984). The weights
of the collected Agapornis sp. egg were between 2
and 3 g and the content of the egg white varied from 0.4
to 1.2 ml. The circumference and diameter of the egg
was found to be 6.57 and 5.4 cm. The total amount of
Standard Lovebird
lysozyme lysozyme
Figure 1. SDS-PAGE of lovebird (Agapornis sp.) egg
white lysozyme with standard lysozyme.
protein present in the crude extract (egg white) of 10
eggs freshly laid of lovebirds was found to be
0.5 mg/ml.
Lysozyme’s basic character is tending to bind to other
proteins in the egg white. As lysozyme is highly stable in
acidic medium, elution was done at pH 5.0 with 5% pyridine
solution with concentrated sulphuric acid from the
active adsorbent of bentonite. The lysozyme was finally
eluted in the supernatant and collected. Enzyme activity
was estimated by lysoplate assay (Li-Chan et al., 1986).
Formation of zone of clearance was observed. The enzyme
activity was estimated by using M. lysodeikitus (cell
wall) as substrate. Lysozyme catalyses the hydrolysis of
N-acetylglucosamine homopolymer and N-acetyl muramic
acid heteropolymer in the cell wall of the bacteria.
This hydrolysis causes the lysis of the bacterial cell wall.
The standard lysozyme and the isolated lysozyme in the
wells diffuse in the medium and the lysis of the bacterial
cell wall is observed as a zone of clearance around the
well. The total amount of protein present in the dialysed
sample was found to be 0.01 mg/ml (from 10 eggs freshly
laid of lovebirds). The enzyme isolated was confirmed to
be lysozyme, which is similar to the molecular weight of
standard lysozyme 14.3 kDa (Figure 1).
This work was aimed to isolate lysozyme from egg and
to compare the concentration, activity of the isolate with
the standard (hen’s egg white) lysozyme (Roy et al.,
2003). The isolation was performed by Alderton et al.
(1944) method and the elution of the lysozyme was high
in acidic medium using 5% aqueous pyridine at pH 5.0.
The activity of the isolated extract was determined by
lysoplate assay where the substrate was incorporated in
the nutrient agar medium. The sensitivity of lysozyme
was determined by its ability to lyse the cell wall of substrate,
which was observed as zone of clearance around
the well. The diameter of the zone of clearance is directly
proportional to the enzyme concentration. This assay
gives a rough estimation about the activity of the enzyme,
as the substrate used as live culture (Ghosh, 2003). The
isolated extract was subjected to concentration by ammonium
sulphate precipitation and partial purification by
conventional dialysis method. After partial purification of
the enzyme, it was subjected to sodium dodecyl poly
acrylamide electrophoresis for the confirmation and
determination of molecular weight of the isolated enzyme
with the standard lysozyme as marker and molecular
weight was determined 14.3 kDa.
The extraction of lysozyme from lovebird (Agapornis
sp.) proves to be promising as it has tremendous application
in various industrial sectors. This work of isolation,
concentration, partial purification of the enzyme suggests
that the activity of the enzyme was found to be effective
using the cell wall of M. lysodeikitus as substrate. The
molecular weight of the isolated enzyme (Lysozyme) was
also determined as 14.3 kDa by SDS-PAGE along with
protein marker (standard lysozyme).