Ovomucoid, molecular weight

The saccharide blocks are obtained by enzymatic (pronase) degradation of ovomucoid extracted from hen egg white followed by column chromatography fractionation and purification Thus two glycoamino acids Oq and Op are obtained. For instance, the (3 fraction (Op) has a molecular weight 3 200 and contains 16 saccharide residues 1 residue of galactose in terminal position, 5 of mannose and 10 of N-acetyl glucoseamine (Fig. 39). 

There appears to be sequence homology between the pineapple stem bromelain inhibitors and some of the small molecular weight inhibitors from the legumlnosae (91) Human inter-a-trypsin inhibitor contains two domains with great similarity to the domains of the Kunitz-type inhibitors (44 92-94)> The ovoinhibitors from Japanese quail and chicken egg whites contain six tandem domains which are homologous to the Kazal pancreatic secretory inhibitor and to the ovomucoids (69) ... 

Ovomucoid is the anti-tryptic factor of egg-white [181, 281, 415], having a molecular weight of between 27,000 and 29,000, and representing approximately 11% of its total protein. This glycoprotein contains about 20% of carbohydrate and it is equally distributed between the thin and thick layers of whole egg-white [189, 586, 587]. Ovomucoid has been the subject of many reviews [172, 388,448,453, 654]. 

Native ovoflavoprotein (49 kDa, pf=5.1) has, as does ovomucoid, certain antinutritional effects, as it inhibits serine proteases (trypsin, chymotrypsin and also microbial proteases) and has antiviral activity. Ovomacroglobulin (ovostatin) is an inhibitor of serine, cysteine, thiol and metalloproteases and shows antimicrobial activity. Some antinutritional effects are also seen in the basic glycoprotein avidin in raw egg white (relative molecular weight of the monomer is 15.6 kDa). It contains four identical subunits (pf = 9.5), each of which binds one molecule of biotin to give an unavailable complex. However, the denatured avidin, for example in hard-boiled eggs, does not interact with biotin. The interaction of riboflavin with flavoprotein (32 kDa, pf = 4.0) has, on the contrary, a positive influence on vitamin stability. Cystatin acts as cysteine protease inhibitor, and shows antimicrobial, antitumor and immunomodulating activities. 

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