Name: L-Cystine (Highly Pure)
Brand: Molecular Depot
SKU: B2014957
Price: 695.00 USD
Availability: InStock

<h2>What are research amino acids and derivatives?</h2>
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Research amino acids and derivatives include the 20 standard proteinogenic L-amino acids used as cell culture supplements, nutritional studies substrates, and biochemical standards; D-amino acids for studying peptide and protein chirality, antimicrobial peptide research, and bacterial cell wall studies; N-protected amino acid derivatives for solid-phase and solution-phase peptide synthesis; and non-canonical or unnatural amino acids for genetic code expansion, bioorthogonal protein labeling, and studying structure-function relationships in proteins.&nbsp;
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<h2 dir="ltr">What you will find:</h2>
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Cell Culture-Grade Amino Acids: Ultra-pure essential and non-essential amino blocks prepared for optimal cellular metabolic performance.
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Protected Amino Derivatives: Chemically shielded monomers optimized for solid-phase peptide synthesis without unwanted side reactions.
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Chiral Isomers &amp; Analogs: High-resolution stereoisomers tailored for exploring enzyme specificity and structural ligand binding.
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Metabolic Tracers: Refined amino derivatives designed for tracking protein synthesis and cellular nutrient uptake pathways.
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<h2>How to choose amino acids and derivatives</h2>
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Use L-Glutamine for cell culture &mdash; but consider the more stable GlutaMAX alternative
L-Glutamine is consumed rapidly by proliferating cells and also degrades spontaneously in aqueous solution at 37&deg;C over days to weeks, forming ammonia that can inhibit cell growth. GlutaMAX (L-alanyl-L-glutamine) is a more stable dipeptide alternative that is cleaved to release glutamine in the culture medium and reduces ammonia accumulation.
Use essential amino acids together when supplementing defined media
The nine essential amino acids (histidine, isoleucine, leucine, lysine, methionine, phenylalanine, threonine, tryptophan, and valine) cannot be synthesized by mammalian cells and must be supplied in culture media, and their concentrations must be balanced since running short of even one essential amino acid halts protein synthesis.
Choose D-amino acids for studying non-L-peptide systems
D-Amino acids are the mirror images of standard L-amino acids and are resistant to protease digestion, making them useful for synthesizing protease-resistant peptide analogs, studying bacterial cell wall biosynthesis involving D-glutamate and D-alanine, and research on antimicrobial peptides and their mode of action.
Use N-protected amino acids (Fmoc or Boc) for solid-phase peptide synthesis
N-protected amino acids with Fmoc (9-fluorenylmethyloxycarbonyl) or Boc (tert-butyloxycarbonyl) protecting groups on the alpha-amino group are the building blocks for automated solid-phase peptide synthesis, with the appropriate protection scheme depending on the synthesis strategy and resin used.
Use non-canonical amino acids for site-specific protein labeling
Non-canonical amino acids bearing bioorthogonal reactive groups, such as azide or alkyne functionalities, can be incorporated into proteins at specific sites by genetic code expansion using engineered aminoacyl-tRNA synthetase systems, enabling site-specific conjugation of labels, payloads, or probes without disrupting protein function.
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<h2>Specifications context</h2>
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L-Glutamine spontaneously cyclizes to pyroglutamate at physiological temperature, releasing ammonia at a rate that depends on temperature and pH, losing approximately 10&ndash;20% of its activity per week at 37&deg;C under standard cell culture conditions. As of 2026, L-alanyl-L-glutamine dipeptide substitutes continue to gain adoption as more stable L-glutamine replacements in cell culture media formulations, particularly in bioproduction settings where medium stability and reduced ammonia accumulation directly affect culture performance.
<a href="https://mbpinc.net/contact-us">Contact the helpful team at MBP</a> today to request a quote for your specific research requirements.

Amino Acids & Derivatives

Molecular Depot

Key Specifications

L-Cystine (Highly Pure)

L-Cystine (Highly Pure) by Molecular Depot is a highly pure L-cystine, the oxidised dimer of L-cysteine, which contributes to the stabilisation of the tertiary structure of proteins. It is used as an amino acid supplement in cell culture and fermentation media, as a redox buffer component in protein refolding and in amino acid analysis. Each unit contains 5 g. MBP supplies Molecular Depot amino acid reagents to research labs in the United States, Canada and worldwide.