. Biological structure and function; proceedings. Biochemistry; Cytology. 342 ALBERT DORFMAN AND SARA SCHILLER to function, I think, because it suggests a connection between morphogenesis and the unique asymmetry of protein molecules. Dorfman: I like this very much and there isn't time to expand on it. Last year we proposed a mechanism for polysaccharide synthesis which envisaged a mechan- ism of this kind. One of the difficulties is that we find no low-molecular weight intermediates. We have to think of an enzyme which somehow or other forms hyaluronic acid on the enzyme while the chain keeps
. Biological structure and function; proceedings. Biochemistry; Cytology. 342 ALBERT DORFMAN AND SARA SCHILLER to function, I think, because it suggests a connection between morphogenesis and the unique asymmetry of protein molecules. Dorfman: I like this very much and there isn't time to expand on it. Last year we proposed a mechanism for polysaccharide synthesis which envisaged a mechan- ism of this kind. One of the difficulties is that we find no low-molecular weight intermediates. We have to think of an enzyme which somehow or other forms hyaluronic acid on the enzyme while the chain keeps getting longer until it is large enough and then is detached from the enzyme. Hestrin : In our laboratory Schramm and Zelinger have found that /3-glucose-i- phosphate can be condensed in the presence of maltose phosphorylase with glucosamine to afford in good yield the ot-glucosyl-i,4-glucosamine. They have also obtained similarly the acetylglucosamine derivative. These materials are thus Cytoplasm Plasma membrane Medium Cell wall polymerizing enzyme ""Xl-s:*^^^ ^"v aJ Cell wall precursors â^^=*'^ Extracellular polysaccharide precursors _ ^^ NO Extracellular polysaccharide ' ^â ^=t^-' polymerizing enzyme. Extracellular polysaccharide Fig. I. now readily available and may be useful for studies designed to elucidate the effect of an a-linkage on the properties of glucosamine-containing polymers. A general comment concerning the interpretation of data obtained in enzyme solution on a substrate of a saccharide synthesis might perhaps be appropriate. There is a tendency to take the view that a demonstration of synthesis in an en- zyme solution suffices to demonstrate that the substrate in question is also the physiological substrate. However, especially if the reaction observed in a solution is sluggish, an observed reaction may be only an artifact. Some of the uridine diphosphoglycoses, for example, can still conceivably merely be analogues of unidentified physiol
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