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tertiary structure --> enzymes

what does it mean that the tertiary structure determines enzymes? Since some enzymes are actually made up of more than 1 polypeptides, wouldn't be correct to say "quanternary structure determines enzymes"?
Original post by BrightBlueStar11
what does it mean that the tertiary structure determines enzymes? Since some enzymes are actually made up of more than 1 polypeptides, wouldn't be correct to say "quanternary structure determines enzymes"?

Not necessarily as the tertiary structure involves the 3D shape of the proteins and hence the different bonds of the r-groups on the amino acids - this essentially determines the shape of the active site
Original post by Babyabz1
Not necessarily as the tertiary structure involves the 3D shape of the proteins and hence the different bonds of the r-groups on the amino acids - this essentially determines the shape of the active site


but wouldn't quaternary structure also determine the shape of the active site?
Original post by BrightBlueStar11
but wouldn't quaternary structure also determine the shape of the active site?


theoretically yes but mainly tertiary as quaretnary depends already on the tertiary structure
Reply 4
Original post by BrightBlueStar11
what does it mean that the tertiary structure determines enzymes? Since some enzymes are actually made up of more than 1 polypeptides, wouldn't be correct to say "quanternary structure determines enzymes"?


We say that tertiary structure of enzymes determines the enzymatic activity as per the lock and key function as each tertiary structure (compact and globular shape) is usually a very specific or unique 3D model which is the further arrangement of secondary structures like alpha helices and beta pleated sheets or folding of protein chain in space into a final structure.

The sequence of amino acids in a protein (the primary structure) will determine where alpha helices and beta sheets (the secondary structures) will occur. And this in turn will influence how the tertiary structure would look like making it always specific depending on the order of arrangement of amino acids in the primary structure.

Quaternary structure would be a complex protein with more than one polypeptide chain or polymeric sub unit which enables it to have multiple functions such as even undergoing complicated conformational changes and also allowing it to be involved in protein function and allosteric inhibition. In these cases the sub unit enzymes could also exhibit cooperative or anti cooperative properties to fulfill the multiple functions.

Since quaternary enzyme is a complex of enzyme sub units where the enzyme sub units themselves even when alone could determine their activity, we say that at the tertiary structure level itself we can determine it’s activity based on the unique structure.


416AF034-0A7B-4604-A306-84896ECEBA6D.jpg.jpeg
Original post by Babyabz1
theoretically yes but mainly tertiary as quaretnary depends already on the tertiary structure


Original post by Redmed_
We say that tertiary structure of enzymes determines the enzymatic activity as per the lock and key function as each tertiary structure (compact and globular shape) is usually a very specific or unique 3D model which is the further arrangement of secondary structures like alpha helices and beta pleated sheets or folding of protein chain in space into a final structure.

The sequence of amino acids in a protein (the primary structure) will determine where alpha helices and beta sheets (the secondary structures) will occur. And this in turn will influence how the tertiary structure would look like making it always specific depending on the order of arrangement of amino acids in the primary structure.

Quaternary structure would be a complex protein with more than one polypeptide chain or polymeric sub unit which enables it to have multiple functions such as even undergoing complicated conformational changes and also allowing it to be involved in protein function and allosteric inhibition. In these cases the sub unit enzymes could also exhibit cooperative or anti cooperative properties to fulfill the multiple functions.

Since quaternary enzyme is a complex of enzyme sub units where the enzyme sub units themselves even when alone could determine their activity, we say that at the tertiary structure level itself we can determine it’s activity based on the unique structure.


416AF034-0A7B-4604-A306-84896ECEBA6D.jpg.jpeg


thank you so much guys :smile:

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