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Chemistry Forums for Students => Organic Chemistry Forum => Topic started by: OCD on January 02, 2007, 02:24:30 AM

Title: What is a proteic unit?
Post by: OCD on January 02, 2007, 02:24:30 AM

The globular proteic structures act as transductors between the external action of receptive structures by drugs and some intercellular metabolic processes.I don't quite get the meaning of this sentence.
 I asked this question before ,and I remember that a proteic unit is a cell killed by proteolytic   enzymes,I'm not sure if that's true.
 

Title: Re: What is a proteic unit?
Post by: Yggdrasil on January 02, 2007, 05:44:20 PM

I've never heard of the term proteic unit before, but I assume it refers to a protein.  Proteins are functional collections of biological macromolecules in the cell.  They are composed of primarily of polypeptides which can be modified in different ways (e.g. phosphorylation, glycosylation, etc).  Sometimes a single polypeptide chain can act as a functional protein (e.g. in the case of myoglobin).  Often, multiple polypeptide chains assemble in a complex to form a functional protein (e.g. in the case of hemoglobin).  Sometimes these assemblies are dynamic (i.e. they assemble, perform their action, recruit new members, perform a new action, then disassemble) or they are static (i.e. unchanging).

So for the first sentence, yes, proteins are important in transducing external stimuli (e.g. the presence of a drug in the extracellular space) to intracellular responses (e.g. transcription of a certain set of genes).  See the wikipedia article on signal transduction (http://en.wikipedia.org/wiki/Signal_transduction) for more information.

Proteolytic enzymes cleave polypeptide chains, often destroying the activity of the proteins they act upon.  However, some proteins (e.g. zymogens) require proteolytic cleavage to convert them from an inactive form to their active form.