Identify the missing substrate or product indicated by ? in each of the enzyme reactions shown below. Select a compound from the list and click the "Submit" button. Note that only the first answer to each question is scored. Questions can be answered in any order.

Gamma-aminobutyrate + ? <---> glutamate + succinic semialdehyde

Alanine 1-Aminocyclopropane-1-carboxylate Asparagine Aspartate Betaine aldehyde Gamma-aminobutyrate Glutamate Glutamine Glycine Homoserine Methionine 2-Oxobutyrate 2-Oxoglutarate Proline Putrescine Pyrroline-5-carboxylate Pyruvate S-Adenosylhomocysteine S-Adenosylmethionine Serine S-Methylmethionine

Score: out of:

Alanine 1-Aminocyclopropane-1-carboxylate Asparagine Aspartate Betaine aldehyde Gamma-aminobutyrate Glutamate Glutamine Glycine Homoserine Methionine 2-Oxobutyrate 2-Oxoglutarate Proline Putrescine Pyrroline-5-carboxylate Pyruvate S-Adenosylhomocysteine S-Adenosylmethionine Serine S-Methylmethionine

Score: out of:

Alanine 1-Aminocyclopropane-1-carboxylate Asparagine Aspartate Betaine aldehyde Gamma-aminobutyrate Glutamate Glutamine Glycine Homoserine Methionine 2-Oxobutyrate 2-Oxoglutarate Proline Putrescine Pyrroline-5-carboxylate Pyruvate S-Adenosylhomocysteine S-Adenosylmethionine Serine S-Methylmethionine

Score: out of:

Alanine 1-Aminocyclopropane-1-carboxylate Asparagine Aspartate Betaine aldehyde Gamma-aminobutyrate Glutamate Glutamine Glycine Homoserine Methionine 2-Oxobutyrate 2-Oxoglutarate Proline Putrescine Pyrroline-5-carboxylate Pyruvate S-Adenosylhomocysteine S-Adenosylmethionine Serine S-Methylmethionine

Score: out of:

Alanine 1-Aminocyclopropane-1-carboxylate Asparagine Aspartate Betaine aldehyde Gamma-aminobutyrate Glutamate Glutamine Glycine Homoserine Methionine 2-Oxobutyrate 2-Oxoglutarate Proline Putrescine Pyrroline-5-carboxylate Pyruvate S-Adenosylhomocysteine S-Adenosylmethionine Serine S-Methylmethionine

Score: out of:

Alanine 1-Aminocyclopropane-1-carboxylate Asparagine Aspartate Betaine aldehyde Gamma-aminobutyrate Glutamate Glutamine Glycine Homoserine Methionine 2-Oxobutyrate 2-Oxoglutarate Proline Putrescine Pyrroline-5-carboxylate Pyruvate S-Adenosylhomocysteine S-Adenosylmethionine Serine S-Methylmethionine

Score: out of:

Alanine 1-Aminocyclopropane-1-carboxylate Asparagine Aspartate Betaine aldehyde Gamma-aminobutyrate Glutamate Glutamine Glycine Homoserine Methionine 2-Oxobutyrate 2-Oxoglutarate Proline Putrescine Pyrroline-5-carboxylate Pyruvate S-Adenosylhomocysteine S-Adenosylmethionine Serine S-Methylmethionine

Score: out of:

Alanine 1-Aminocyclopropane-1-carboxylate Asparagine Aspartate Betaine aldehyde Gamma-aminobutyrate Glutamate Glutamine Glycine Homoserine Methionine 2-Oxobutyrate 2-Oxoglutarate Proline Putrescine Pyrroline-5-carboxylate Pyruvate S-Adenosylhomocysteine S-Adenosylmethionine Serine S-Methylmethionine

Score: out of:

Alanine 1-Aminocyclopropane-1-carboxylate Asparagine Aspartate Betaine aldehyde Gamma-aminobutyrate Glutamate Glutamine Glycine Homoserine Methionine 2-Oxobutyrate 2-Oxoglutarate Proline Putrescine Pyrroline-5-carboxylate Pyruvate S-Adenosylhomocysteine S-Adenosylmethionine Serine S-Methylmethionine

Score: out of:

Alanine 1-Aminocyclopropane-1-carboxylate Asparagine Aspartate Betaine aldehyde Gamma-aminobutyrate Glutamate Glutamine Glycine Homoserine Methionine 2-Oxobutyrate 2-Oxoglutarate Proline Putrescine Pyrroline-5-carboxylate Pyruvate S-Adenosylhomocysteine S-Adenosylmethionine Serine S-Methylmethionine

Score: out of: