livingdeadbeat

Hi, In a test in our a-level class we had to use gelatine because we didn't have proline. We used acid hydrolysis to break down the polymer, which i believe has glycine and proline in it in roughly equal measures. Then we added ninhydrin, which produced a yellowish colour. Now i know why proline doesn't produce the purple colour, but what i don't get is how come this works? Because Glycine is a primary amino and its also present in gelatine, so surely when we performed acid hydrolysis the result would be equal (roughly) amounts of proline and glycine. How come the glycine didn't react as well and turn the solution purple? Thanks for any help.

Ok dude, thanks alot for your help

Cool thanks. But why does it turn brownish yellow?

Hi everyone, Another question. In writing about ninhydrin and amino acids that form the subunits of proteins i was wondering what it is that makes proline produce a brownish colour? From what i've read i think the purple that it usually gives with primary amino groups is due to the ninhydrin reacting with the N in the amine. I'm guessing, cos proline has a ring structure that makes the anime a secondary the N isn't available for it to reaction and form the purple... Is the above correct and what makes it go brown? Thanks for any help

Ah all makes sense now! Thanks alot for taking the time to explain that. Haha you wouldn't believe how many times i've typo'd amine through this assignment.

Hi forum, I have ,probably, a very simple question for you lot to answer but i can't find an explanation i understand well enough on the net. I've just started biology at college and i'm writing about amino acids. Through research in my "Life" book i see that they have two functional groups, one being animo. Then looking online i see lots of sites talking about amines, which seem to also be NH with the no of H dependant on if they are primary or secondary etc. ? I'm confused with the difference between amines and amino groups. Could someone please explain this to me. Thanks alot.