G growingpains Full Member 10+ Year Member Joined Dec 22, 2011 Messages 57 Reaction score 0 Mar 27, 2012 #1 Why isn't serine's side chain ionizable if it's more basic than cysteine's side chain (which is ionizable)? Members don't see this ad.
Why isn't serine's side chain ionizable if it's more basic than cysteine's side chain (which is ionizable)? Members don't see this ad.
MedPR Membership Revoked Removed 10+ Year Member Joined Dec 1, 2011 Messages 18,579 Reaction score 57 Mar 27, 2012 #2 growingpains said: Why isn't serine's side chain ionizable if it's more basic than cysteine's side chain (which is ionizable)? Click to expand... Where did you read that serine isn't ionizable? Upvote 0 Downvote
growingpains said: Why isn't serine's side chain ionizable if it's more basic than cysteine's side chain (which is ionizable)? Click to expand... Where did you read that serine isn't ionizable?
G growingpains Full Member 10+ Year Member Joined Dec 22, 2011 Messages 57 Reaction score 0 Mar 27, 2012 #3 "Another subgroup of the amino acids are those with ionizable side chains. These include: aspartate, glutamate, histidine, cysteine, lysine, tyrosine and arginine." (http://webhost.bridgew.edu/fgorga/proteins/aminoacids.htm) "There are only 7 amino acids with ionizable side chains" -BR Upvote 0 Downvote
"Another subgroup of the amino acids are those with ionizable side chains. These include: aspartate, glutamate, histidine, cysteine, lysine, tyrosine and arginine." (http://webhost.bridgew.edu/fgorga/proteins/aminoacids.htm) "There are only 7 amino acids with ionizable side chains" -BR
MedPR Membership Revoked Removed 10+ Year Member Joined Dec 1, 2011 Messages 18,579 Reaction score 57 Mar 27, 2012 #4 growingpains said: "Another subgroup of the amino acids are those with ionizable side chains. These include: aspartate, glutamate, histidine, cysteine, lysine, tyrosine and arginine." (http://webhost.bridgew.edu/fgorga/proteins/aminoacids.htm) "There are only 7 amino acids with ionizable side chains" -BR Click to expand... Well I don't know, but apparently threonine isn't ionizable either and threonine has a hydroxyl group on the sidechain just like serine does. Upvote 0 Downvote
growingpains said: "Another subgroup of the amino acids are those with ionizable side chains. These include: aspartate, glutamate, histidine, cysteine, lysine, tyrosine and arginine." (http://webhost.bridgew.edu/fgorga/proteins/aminoacids.htm) "There are only 7 amino acids with ionizable side chains" -BR Click to expand... Well I don't know, but apparently threonine isn't ionizable either and threonine has a hydroxyl group on the sidechain just like serine does.
theseeker4 PGY 3 Verified Member 10+ Year Member Physician Joined Apr 20, 2011 Messages 3,499 Reaction score 770 Mar 28, 2012 #5 growingpains said: Why isn't serine's side chain ionizable if it's more basic than cysteine's side chain (which is ionizable)? Click to expand... Serine's chain is more BASIC than cysteine's, meaning it is less acidic, and therefore less likely to lose its proton. Upvote 0 Downvote
growingpains said: Why isn't serine's side chain ionizable if it's more basic than cysteine's side chain (which is ionizable)? Click to expand... Serine's chain is more BASIC than cysteine's, meaning it is less acidic, and therefore less likely to lose its proton.
MedPR Membership Revoked Removed 10+ Year Member Joined Dec 1, 2011 Messages 18,579 Reaction score 57 Mar 28, 2012 #6 theseeker4 said: Serine's chain is more BASIC than cysteine's, meaning it is less acidic, and therefore less likely to lose its proton. Click to expand... But aren't alcohols pretty ionizable in water? Upvote 0 Downvote
theseeker4 said: Serine's chain is more BASIC than cysteine's, meaning it is less acidic, and therefore less likely to lose its proton. Click to expand... But aren't alcohols pretty ionizable in water?
P pfaction Full Member 10+ Year Member Joined Mar 14, 2010 Messages 2,225 Reaction score 79 Mar 28, 2012 #7 I've read that no, they're not. Not even NaOH will tear apart ROH's, according to TPR Organic Chemistry. Upvote 0 Downvote
I've read that no, they're not. Not even NaOH will tear apart ROH's, according to TPR Organic Chemistry.
theseeker4 PGY 3 Verified Member 10+ Year Member Physician Joined Apr 20, 2011 Messages 3,499 Reaction score 770 Mar 28, 2012 #8 MedPR said: But aren't alcohols pretty ionizable in water? Click to expand... They are quite tightly bound, actually. Very difficult to de-protonate an alcohol. Upvote 0 Downvote
MedPR said: But aren't alcohols pretty ionizable in water? Click to expand... They are quite tightly bound, actually. Very difficult to de-protonate an alcohol.
C chiddler Full Member 10+ Year Member Joined Apr 6, 2010 Messages 2,439 Reaction score 4 Mar 28, 2012 #9 theseeker4 said: They are quite tightly bound, actually. Very difficult to de-protonate an alcohol. Click to expand... Do you know the threshold pKa that hydroxide will deprotonate? Upvote 0 Downvote
theseeker4 said: They are quite tightly bound, actually. Very difficult to de-protonate an alcohol. Click to expand... Do you know the threshold pKa that hydroxide will deprotonate?
P pfaction Full Member 10+ Year Member Joined Mar 14, 2010 Messages 2,225 Reaction score 79 Mar 28, 2012 #10 TPR: An alkoxide ion is a poor leaving group. Conjbase of alcohol, a fairly weak acid pKa 15-19 Upvote 0 Downvote