Preprohormone, Prohormone, and Hormone

[agp]

I stumbled across this while studying for my endocrine hormones... A preprohormone is a precursor to a prohormone, which is a precursor to a hormone. But what's the difference between a preprohormone and prohormone? Is a preprohormone a strand of polypeptides including exons and introns, and prohormone a strand of polypeptides without introns (but still is not a functional hormone)? Please help..

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[Charles_Carmichael]

Introns and exons are in RNA, not in peptides. Prepro- and pro-hormones are peptides, so they will not have introns and exons. They have additional amino acids that are cleaved off or they're modified in some other way before becoming a functional hormone.

 

[BennieBlanco]

I stumbled across this while studying for my endocrine hormones... A preprohormone is a precursor to a prohormone, which is a precursor to a hormone. But what's the difference between a preprohormone and prohormone? Is a preprohormone a strand of polypeptides including exons and introns, and prohormone a strand of polypeptides without introns (but still is not a functional hormone)? Please help..

Lets say that the hormone we see floating around in your body is: CCC

Lets say the original peptide that is formed is: AAAAABBBBCCC

The hormone would be CCC and the preprohormone would be AAAAABBBBCCC.

Basically the preprohormone is cleaved once and transiently exists as a prohormone (BBBBCCC). Since there is an intermediate they needed two names (prepro and pro).

Summary:

Prepro: AAAAABBBBCCC
pro: BBBBCCC
hormone: CCC

think cleave not intron/exon. In real life AAAAA and BBBB may actually have functions, they typically are not junk.

 

[PiBond]

Bennie is correct. It is cleaved twice in the ER (I believe). The uncleaved (and longest) is Pre-, first cleave (next longest) is pro, hormone is what's left after two cleaves.

Lets say that the hormone we see floating around in your body is: CCC

Lets say the original peptide that is formed is: AAAAABBBBCCC

The hormone would be CCC and the preprohormone would be AAAAABBBBCCC.

Basically the preprohormone is cleaved once and transiently exists as a prohormone (BBBBCCC). Since there is an intermediate they needed two names (prepro and pro).

Summary:

Prepro: AAAAABBBBCCC
pro: BBBBCCC
hormone: CCC

think cleave not intron/exon. In real life AAAAA and BBBB may actually have functions, they typically are not junk.

 

[agp]

So both preprohormone and prohormone are just two forms of precursors of the hormone differing only in their amino acid chain.. Am I correct?

 

[PiBond]

Yes. It's modified twice in the ER lumen before becoming the peptide hormone we know and love

So both preprohormone and prohormone are just two forms of precursors of the hormone differing only in their amino acid chain.. Am I correct?