J. Biol. Chem. 274, 6754-6762 (1999)[PubMed:10037775]
Delta1-Pyrroline-5-carboxylate synthase (P5CS; EC not assigned), a mitochondrial inner membrane, ATP- and NADPH-dependent, bifunctional enzyme, catalyzes the reduction of glutamate to Delta1-pyrroline-5-carboxylate, a critical step in the de novo biosynthesis of proline and ornithine. We utilized published plant P5CS sequence to search the expressed sequence tag data base and cloned two full-length human P5CS cDNAs differing in length by 6 base pairs (bp) in the open reading frame. The short cDNA has a 2379-bp open reading frame encoding a protein of 793 residues; the long cDNA, generated by "exon sliding," a form of alternative splicing, contains an additional 6-bp insert following bp +711 of the short form resulting in inclusion of two additional amino acids in the region predicted to be the gamma-glutamyl kinase active site of P5CS. The long form predominates in all tissues examined except gut. We also isolated the corresponding long and short murine P5CS transcripts. To confirm the identity of the putative P5CS cDNAs, we expressed both human forms in gamma-glutamyl kinase- and gamma-glutamyl phosphate reductase-deficient strains of Saccharomyces cerevisiae and showed that they conferred the proline prototrophy. Additionally, we found expression of the murine putative P5CS cDNAs conferred proline prototrophy to P5CS-deficient Chinese hamster ovary cells (CHO-K1). We utilized stable CHO-K1 cell transformants to compare the biochemical characteristics of the long and short murine P5CS isoforms. We found that both confer P5CS activity and that the short isoform is inhibited by L-ornithine with a Ki of approximately 0.25 mM. Surprisingly, the long isoform is insensitive to ornithine inhibition. Thus, the two amino acid insert in the long isoform abolishes feedback inhibition of P5CS activity by L-ornithine.
delta(1)-pyrroline-5-carboxylate synthase (P5CS), a bifunctional ATP- and NADPH-dependent mitochondrial enzyme, catalyzes the reduction of glutamate to delta(1)-pyrroline-5-carboxylate, a critical step in the biosynthesis of proline, ornithine and arginine. Recently, we reported the cloning and expression of human and murine P5CS cDNAs. Previously, we showed that mammalian P5CS undergoes alternative splicing to generate two isoforms differing only by a 2 amino acid insert at the N-terminus of the gamma-glutamyl kinase active site. The short isoform has high activity in the gut, where it participates in arginine biosynthesis and is inhibited by ornithine. The long isoform, expressed in multiple tissues, is necessary for the synthesis of proline from glutamate and is insensitive to ornithine. Here, we describe a newly recognized inborn error due to the deficiency of P5CS in two siblings with progressive neurodegeneration, joint laxity, skin hyperelasticity and bilateral subcapsular cataracts. Their metabolic phenotype includes hyperammonemia, hypoornithinemia, hypocitrullinemia, hypoargininemia and hypoprolinemia. Both are homozygous for the missense mutation, R84Q, which alters a conserved residue in the P5CS gamma-glutamyl kinase domain. R84Q is not present in 194 control chromosomes and dramatically reduces the activity of both P5CS isoforms when expressed in mammalian cells. Additionally, R84Q appears to destabilize the long isoform. This is the first documented report of an inborn error of P5CS and suggests that this disorder should be considered in the differential diagnosis in patients with neurodegeneration and/or cataracts and connective tissue disease.
delta(1)-pyrroline-5-carboxylate synthase (P5CS), a bifunctional ATP- and NADPH-dependent mitochondrial enzyme, catalyzes the reduction of glutamate to delta(1)-pyrroline-5-carboxylate, a critical step in the biosynthesis of proline, ornithine and arginine. Recently, we reported the cloning and expression of human and murine P5CS cDNAs. Previously, we showed that mammalian P5CS undergoes alternative splicing to generate two isoforms differing only by a 2 amino acid insert at the N-terminus of the gamma-glutamyl kinase active site. The short isoform has high activity in the gut, where it participates in arginine biosynthesis and is inhibited by ornithine. The long isoform, expressed in multiple tissues, is necessary for the synthesis of proline from glutamate and is insensitive to ornithine. Here, we describe a newly recognized inborn error due to the deficiency of P5CS in two siblings with progressive neurodegeneration, joint laxity, skin hyperelasticity and bilateral subcapsular cataracts. Their metabolic phenotype includes hyperammonemia, hypoornithinemia, hypocitrullinemia, hypoargininemia and hypoprolinemia. Both are homozygous for the missense mutation, R84Q, which alters a conserved residue in the P5CS gamma-glutamyl kinase domain. R84Q is not present in 194 control chromosomes and dramatically reduces the activity of both P5CS isoforms when expressed in mammalian cells. Additionally, R84Q appears to destabilize the long isoform. This is the first documented report of an inborn error of P5CS and suggests that this disorder should be considered in the differential diagnosis in patients with neurodegeneration and/or cataracts and connective tissue disease.
delta(1)-pyrroline-5-carboxylate synthase (P5CS), a bifunctional ATP- and NADPH-dependent mitochondrial enzyme, catalyzes the reduction of glutamate to delta(1)-pyrroline-5-carboxylate, a critical step in the biosynthesis of proline, ornithine and arginine. Recently, we reported the cloning and expression of human and murine P5CS cDNAs. Previously, we showed that mammalian P5CS undergoes alternative splicing to generate two isoforms differing only by a 2 amino acid insert at the N-terminus of the gamma-glutamyl kinase active site. The short isoform has high activity in the gut, where it participates in arginine biosynthesis and is inhibited by ornithine. The long isoform, expressed in multiple tissues, is necessary for the synthesis of proline from glutamate and is insensitive to ornithine. Here, we describe a newly recognized inborn error due to the deficiency of P5CS in two siblings with progressive neurodegeneration, joint laxity, skin hyperelasticity and bilateral subcapsular cataracts. Their metabolic phenotype includes hyperammonemia, hypoornithinemia, hypocitrullinemia, hypoargininemia and hypoprolinemia. Both are homozygous for the missense mutation, R84Q, which alters a conserved residue in the P5CS gamma-glutamyl kinase domain. R84Q is not present in 194 control chromosomes and dramatically reduces the activity of both P5CS isoforms when expressed in mammalian cells. Additionally, R84Q appears to destabilize the long isoform. This is the first documented report of an inborn error of P5CS and suggests that this disorder should be considered in the differential diagnosis in patients with neurodegeneration and/or cataracts and connective tissue disease.
delta(1)-pyrroline-5-carboxylate synthase (P5CS), a bifunctional ATP- and NADPH-dependent mitochondrial enzyme, catalyzes the reduction of glutamate to delta(1)-pyrroline-5-carboxylate, a critical step in the biosynthesis of proline, ornithine and arginine. Recently, we reported the cloning and expression of human and murine P5CS cDNAs. Previously, we showed that mammalian P5CS undergoes alternative splicing to generate two isoforms differing only by a 2 amino acid insert at the N-terminus of the gamma-glutamyl kinase active site. The short isoform has high activity in the gut, where it participates in arginine biosynthesis and is inhibited by ornithine. The long isoform, expressed in multiple tissues, is necessary for the synthesis of proline from glutamate and is insensitive to ornithine. Here, we describe a newly recognized inborn error due to the deficiency of P5CS in two siblings with progressive neurodegeneration, joint laxity, skin hyperelasticity and bilateral subcapsular cataracts. Their metabolic phenotype includes hyperammonemia, hypoornithinemia, hypocitrullinemia, hypoargininemia and hypoprolinemia. Both are homozygous for the missense mutation, R84Q, which alters a conserved residue in the P5CS gamma-glutamyl kinase domain. R84Q is not present in 194 control chromosomes and dramatically reduces the activity of both P5CS isoforms when expressed in mammalian cells. Additionally, R84Q appears to destabilize the long isoform. This is the first documented report of an inborn error of P5CS and suggests that this disorder should be considered in the differential diagnosis in patients with neurodegeneration and/or cataracts and connective tissue disease.
delta(1)-pyrroline-5-carboxylate synthase (P5CS), a bifunctional ATP- and NADPH-dependent mitochondrial enzyme, catalyzes the reduction of glutamate to delta(1)-pyrroline-5-carboxylate, a critical step in the biosynthesis of proline, ornithine and arginine. Recently, we reported the cloning and expression of human and murine P5CS cDNAs. Previously, we showed that mammalian P5CS undergoes alternative splicing to generate two isoforms differing only by a 2 amino acid insert at the N-terminus of the gamma-glutamyl kinase active site. The short isoform has high activity in the gut, where it participates in arginine biosynthesis and is inhibited by ornithine. The long isoform, expressed in multiple tissues, is necessary for the synthesis of proline from glutamate and is insensitive to ornithine. Here, we describe a newly recognized inborn error due to the deficiency of P5CS in two siblings with progressive neurodegeneration, joint laxity, skin hyperelasticity and bilateral subcapsular cataracts. Their metabolic phenotype includes hyperammonemia, hypoornithinemia, hypocitrullinemia, hypoargininemia and hypoprolinemia. Both are homozygous for the missense mutation, R84Q, which alters a conserved residue in the P5CS gamma-glutamyl kinase domain. R84Q is not present in 194 control chromosomes and dramatically reduces the activity of both P5CS isoforms when expressed in mammalian cells. Additionally, R84Q appears to destabilize the long isoform. This is the first documented report of an inborn error of P5CS and suggests that this disorder should be considered in the differential diagnosis in patients with neurodegeneration and/or cataracts and connective tissue disease.
The chemical reactions and pathways resulting in the formation of L-proline, an L-enantiomer of a chiral, cyclic, nonessential alpha-amino acid found in peptide linkage in proteins.
The chemical reactions and pathways resulting in the formation of ornithine, an amino acid only rarely found in proteins, but which is important in living organisms as an intermediate in the reactions of the urea cycle and in arginine biosynthesis.
Evidence
1:
Inferred from Mutant PhenotypeUniProtKB
delta(1)-pyrroline-5-carboxylate synthase (P5CS), a bifunctional ATP- and NADPH-dependent mitochondrial enzyme, catalyzes the reduction of glutamate to delta(1)-pyrroline-5-carboxylate, a critical step in the biosynthesis of proline, ornithine and arginine. Recently, we reported the cloning and expression of human and murine P5CS cDNAs. Previously, we showed that mammalian P5CS undergoes alternative splicing to generate two isoforms differing only by a 2 amino acid insert at the N-terminus of the gamma-glutamyl kinase active site. The short isoform has high activity in the gut, where it participates in arginine biosynthesis and is inhibited by ornithine. The long isoform, expressed in multiple tissues, is necessary for the synthesis of proline from glutamate and is insensitive to ornithine. Here, we describe a newly recognized inborn error due to the deficiency of P5CS in two siblings with progressive neurodegeneration, joint laxity, skin hyperelasticity and bilateral subcapsular cataracts. Their metabolic phenotype includes hyperammonemia, hypoornithinemia, hypocitrullinemia, hypoargininemia and hypoprolinemia. Both are homozygous for the missense mutation, R84Q, which alters a conserved residue in the P5CS gamma-glutamyl kinase domain. R84Q is not present in 194 control chromosomes and dramatically reduces the activity of both P5CS isoforms when expressed in mammalian cells. Additionally, R84Q appears to destabilize the long isoform. This is the first documented report of an inborn error of P5CS and suggests that this disorder should be considered in the differential diagnosis in patients with neurodegeneration and/or cataracts and connective tissue disease.
The chemical reactions and pathways resulting in the formation of proline (pyrrolidine-2-carboxylic acid), a chiral, cyclic, nonessential alpha-amino acid found in peptide linkage in proteins.
Evidence
1:
Inferred from Mutant PhenotypeUniProtKB
delta(1)-pyrroline-5-carboxylate synthase (P5CS), a bifunctional ATP- and NADPH-dependent mitochondrial enzyme, catalyzes the reduction of glutamate to delta(1)-pyrroline-5-carboxylate, a critical step in the biosynthesis of proline, ornithine and arginine. Recently, we reported the cloning and expression of human and murine P5CS cDNAs. Previously, we showed that mammalian P5CS undergoes alternative splicing to generate two isoforms differing only by a 2 amino acid insert at the N-terminus of the gamma-glutamyl kinase active site. The short isoform has high activity in the gut, where it participates in arginine biosynthesis and is inhibited by ornithine. The long isoform, expressed in multiple tissues, is necessary for the synthesis of proline from glutamate and is insensitive to ornithine. Here, we describe a newly recognized inborn error due to the deficiency of P5CS in two siblings with progressive neurodegeneration, joint laxity, skin hyperelasticity and bilateral subcapsular cataracts. Their metabolic phenotype includes hyperammonemia, hypoornithinemia, hypocitrullinemia, hypoargininemia and hypoprolinemia. Both are homozygous for the missense mutation, R84Q, which alters a conserved residue in the P5CS gamma-glutamyl kinase domain. R84Q is not present in 194 control chromosomes and dramatically reduces the activity of both P5CS isoforms when expressed in mammalian cells. Additionally, R84Q appears to destabilize the long isoform. This is the first documented report of an inborn error of P5CS and suggests that this disorder should be considered in the differential diagnosis in patients with neurodegeneration and/or cataracts and connective tissue disease.
delta(1)-pyrroline-5-carboxylate synthase (P5CS), a bifunctional ATP- and NADPH-dependent mitochondrial enzyme, catalyzes the reduction of glutamate to delta(1)-pyrroline-5-carboxylate, a critical step in the biosynthesis of proline, ornithine and arginine. Recently, we reported the cloning and expression of human and murine P5CS cDNAs. Previously, we showed that mammalian P5CS undergoes alternative splicing to generate two isoforms differing only by a 2 amino acid insert at the N-terminus of the gamma-glutamyl kinase active site. The short isoform has high activity in the gut, where it participates in arginine biosynthesis and is inhibited by ornithine. The long isoform, expressed in multiple tissues, is necessary for the synthesis of proline from glutamate and is insensitive to ornithine. Here, we describe a newly recognized inborn error due to the deficiency of P5CS in two siblings with progressive neurodegeneration, joint laxity, skin hyperelasticity and bilateral subcapsular cataracts. Their metabolic phenotype includes hyperammonemia, hypoornithinemia, hypocitrullinemia, hypoargininemia and hypoprolinemia. Both are homozygous for the missense mutation, R84Q, which alters a conserved residue in the P5CS gamma-glutamyl kinase domain. R84Q is not present in 194 control chromosomes and dramatically reduces the activity of both P5CS isoforms when expressed in mammalian cells. Additionally, R84Q appears to destabilize the long isoform. This is the first documented report of an inborn error of P5CS and suggests that this disorder should be considered in the differential diagnosis in patients with neurodegeneration and/or cataracts and connective tissue disease.
J. Biol. Chem. 274, 6754-6762 (1999)[PubMed:10037775]
Delta1-Pyrroline-5-carboxylate synthase (P5CS; EC not assigned), a mitochondrial inner membrane, ATP- and NADPH-dependent, bifunctional enzyme, catalyzes the reduction of glutamate to Delta1-pyrroline-5-carboxylate, a critical step in the de novo biosynthesis of proline and ornithine. We utilized published plant P5CS sequence to search the expressed sequence tag data base and cloned two full-length human P5CS cDNAs differing in length by 6 base pairs (bp) in the open reading frame. The short cDNA has a 2379-bp open reading frame encoding a protein of 793 residues; the long cDNA, generated by "exon sliding," a form of alternative splicing, contains an additional 6-bp insert following bp +711 of the short form resulting in inclusion of two additional amino acids in the region predicted to be the gamma-glutamyl kinase active site of P5CS. The long form predominates in all tissues examined except gut. We also isolated the corresponding long and short murine P5CS transcripts. To confirm the identity of the putative P5CS cDNAs, we expressed both human forms in gamma-glutamyl kinase- and gamma-glutamyl phosphate reductase-deficient strains of Saccharomyces cerevisiae and showed that they conferred the proline prototrophy. Additionally, we found expression of the murine putative P5CS cDNAs conferred proline prototrophy to P5CS-deficient Chinese hamster ovary cells (CHO-K1). We utilized stable CHO-K1 cell transformants to compare the biochemical characteristics of the long and short murine P5CS isoforms. We found that both confer P5CS activity and that the short isoform is inhibited by L-ornithine with a Ki of approximately 0.25 mM. Surprisingly, the long isoform is insensitive to ornithine inhibition. Thus, the two amino acid insert in the long isoform abolishes feedback inhibition of P5CS activity by L-ornithine.
J. Biol. Chem. 274, 6754-6762 (1999)[PubMed:10037775]
Delta1-Pyrroline-5-carboxylate synthase (P5CS; EC not assigned), a mitochondrial inner membrane, ATP- and NADPH-dependent, bifunctional enzyme, catalyzes the reduction of glutamate to Delta1-pyrroline-5-carboxylate, a critical step in the de novo biosynthesis of proline and ornithine. We utilized published plant P5CS sequence to search the expressed sequence tag data base and cloned two full-length human P5CS cDNAs differing in length by 6 base pairs (bp) in the open reading frame. The short cDNA has a 2379-bp open reading frame encoding a protein of 793 residues; the long cDNA, generated by "exon sliding," a form of alternative splicing, contains an additional 6-bp insert following bp +711 of the short form resulting in inclusion of two additional amino acids in the region predicted to be the gamma-glutamyl kinase active site of P5CS. The long form predominates in all tissues examined except gut. We also isolated the corresponding long and short murine P5CS transcripts. To confirm the identity of the putative P5CS cDNAs, we expressed both human forms in gamma-glutamyl kinase- and gamma-glutamyl phosphate reductase-deficient strains of Saccharomyces cerevisiae and showed that they conferred the proline prototrophy. Additionally, we found expression of the murine putative P5CS cDNAs conferred proline prototrophy to P5CS-deficient Chinese hamster ovary cells (CHO-K1). We utilized stable CHO-K1 cell transformants to compare the biochemical characteristics of the long and short murine P5CS isoforms. We found that both confer P5CS activity and that the short isoform is inhibited by L-ornithine with a Ki of approximately 0.25 mM. Surprisingly, the long isoform is insensitive to ornithine inhibition. Thus, the two amino acid insert in the long isoform abolishes feedback inhibition of P5CS activity by L-ornithine.
delta(1)-pyrroline-5-carboxylate synthase (P5CS), a bifunctional ATP- and NADPH-dependent mitochondrial enzyme, catalyzes the reduction of glutamate to delta(1)-pyrroline-5-carboxylate, a critical step in the biosynthesis of proline, ornithine and arginine. Recently, we reported the cloning and expression of human and murine P5CS cDNAs. Previously, we showed that mammalian P5CS undergoes alternative splicing to generate two isoforms differing only by a 2 amino acid insert at the N-terminus of the gamma-glutamyl kinase active site. The short isoform has high activity in the gut, where it participates in arginine biosynthesis and is inhibited by ornithine. The long isoform, expressed in multiple tissues, is necessary for the synthesis of proline from glutamate and is insensitive to ornithine. Here, we describe a newly recognized inborn error due to the deficiency of P5CS in two siblings with progressive neurodegeneration, joint laxity, skin hyperelasticity and bilateral subcapsular cataracts. Their metabolic phenotype includes hyperammonemia, hypoornithinemia, hypocitrullinemia, hypoargininemia and hypoprolinemia. Both are homozygous for the missense mutation, R84Q, which alters a conserved residue in the P5CS gamma-glutamyl kinase domain. R84Q is not present in 194 control chromosomes and dramatically reduces the activity of both P5CS isoforms when expressed in mammalian cells. Additionally, R84Q appears to destabilize the long isoform. This is the first documented report of an inborn error of P5CS and suggests that this disorder should be considered in the differential diagnosis in patients with neurodegeneration and/or cataracts and connective tissue disease.
Isoform
Long
Is insensitive to ornithine inhibition. This is due to the two amino acid insert which abolishes feedback inhibition of P5CS activity by L-ornithine.
J. Biol. Chem. 274, 6754-6762 (1999)[PubMed:10037775]
Delta1-Pyrroline-5-carboxylate synthase (P5CS; EC not assigned), a mitochondrial inner membrane, ATP- and NADPH-dependent, bifunctional enzyme, catalyzes the reduction of glutamate to Delta1-pyrroline-5-carboxylate, a critical step in the de novo biosynthesis of proline and ornithine. We utilized published plant P5CS sequence to search the expressed sequence tag data base and cloned two full-length human P5CS cDNAs differing in length by 6 base pairs (bp) in the open reading frame. The short cDNA has a 2379-bp open reading frame encoding a protein of 793 residues; the long cDNA, generated by "exon sliding," a form of alternative splicing, contains an additional 6-bp insert following bp +711 of the short form resulting in inclusion of two additional amino acids in the region predicted to be the gamma-glutamyl kinase active site of P5CS. The long form predominates in all tissues examined except gut. We also isolated the corresponding long and short murine P5CS transcripts. To confirm the identity of the putative P5CS cDNAs, we expressed both human forms in gamma-glutamyl kinase- and gamma-glutamyl phosphate reductase-deficient strains of Saccharomyces cerevisiae and showed that they conferred the proline prototrophy. Additionally, we found expression of the murine putative P5CS cDNAs conferred proline prototrophy to P5CS-deficient Chinese hamster ovary cells (CHO-K1). We utilized stable CHO-K1 cell transformants to compare the biochemical characteristics of the long and short murine P5CS isoforms. We found that both confer P5CS activity and that the short isoform is inhibited by L-ornithine with a Ki of approximately 0.25 mM. Surprisingly, the long isoform is insensitive to ornithine inhibition. Thus, the two amino acid insert in the long isoform abolishes feedback inhibition of P5CS activity by L-ornithine.
J. Biol. Chem. 274, 6754-6762 (1999)[PubMed:10037775]
Delta1-Pyrroline-5-carboxylate synthase (P5CS; EC not assigned), a mitochondrial inner membrane, ATP- and NADPH-dependent, bifunctional enzyme, catalyzes the reduction of glutamate to Delta1-pyrroline-5-carboxylate, a critical step in the de novo biosynthesis of proline and ornithine. We utilized published plant P5CS sequence to search the expressed sequence tag data base and cloned two full-length human P5CS cDNAs differing in length by 6 base pairs (bp) in the open reading frame. The short cDNA has a 2379-bp open reading frame encoding a protein of 793 residues; the long cDNA, generated by "exon sliding," a form of alternative splicing, contains an additional 6-bp insert following bp +711 of the short form resulting in inclusion of two additional amino acids in the region predicted to be the gamma-glutamyl kinase active site of P5CS. The long form predominates in all tissues examined except gut. We also isolated the corresponding long and short murine P5CS transcripts. To confirm the identity of the putative P5CS cDNAs, we expressed both human forms in gamma-glutamyl kinase- and gamma-glutamyl phosphate reductase-deficient strains of Saccharomyces cerevisiae and showed that they conferred the proline prototrophy. Additionally, we found expression of the murine putative P5CS cDNAs conferred proline prototrophy to P5CS-deficient Chinese hamster ovary cells (CHO-K1). We utilized stable CHO-K1 cell transformants to compare the biochemical characteristics of the long and short murine P5CS isoforms. We found that both confer P5CS activity and that the short isoform is inhibited by L-ornithine with a Ki of approximately 0.25 mM. Surprisingly, the long isoform is insensitive to ornithine inhibition. Thus, the two amino acid insert in the long isoform abolishes feedback inhibition of P5CS activity by L-ornithine.
Protein involved in the synthesis of naturally-occuring amino acids. In addition to their use for protein biosynthesis, they are the precursors of many molecules such as purines, pyrimidines, histamines, adrenaline and melanin.
Protein involved in the biosynthesis of the cyclic amino acid proline. The structure of proline differs from the structure of other amino acids in that its side chain is bonded to the nitrogen of the amino group as well as to the carbon atom. This makes the amino group a secondary amine, and because of this, proline is also described as an imino acid. The presence of proline residues strongly influences the secondary structure of proteins.
A reference proteome is a set of protein sequences derived from a complete proteome which constitutes a defined standard for a particular user community. Reference proteomes are manually defined according to a number of criteria. They cover the proteomes of well- studied model organisms and other proteomes of interest for biomedical and biotechnological research. Reference proteomes have been selected to provide broad coverage of the tree of life, and constitute a representative cross-section of the taxonomic diversity to be found within UniProtKB.
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