Microbial flavoproteins

Figure 1. Functions of animal, plant, and microbial flavoproteins and...

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. 

Actually, these primary dehydrogenases (quinoproteins or flavoprotein-cytochrome c complexes) and also the terminal oxidases (y-type UOX or CIO) all are found in only the small microbial world, restricted only in a-, and y-Proteobacteria,... 

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