Core Enzymes in Molecular Biology

Behind every breakthrough in genetic engineering and molecular diagnostics lies a set of specialized enzymes. These powerful biological catalysts are the backbone of genetic research and modern biotechnology, enabling critical processes from basic DNA replication to recombinant DNA technology and gene expression studies.

The table below breaks down their key functions, biological roles, and common applications in the laboratory:

Small enzymes. Big impact.

Powering the science that shapes our future.

more:

• What is the difference between Exonuclease and Endonuclease?
• Why is Taq Polymerase used in PCR?

In the world of molecular biology, the stability of enzymes is a critical factor that dictates the efficiency of laboratory workflows and the cost-effectiveness of diagnostic kits. Among these enzymes, RNase A is indispensable for its ability to specifically degrade RNA contamination during DNA and protein purification.

What is RNase A and How Does It Work?

RNase A is a highly efficient ribonuclease that targets single-stranded RNA (ssRNA). It works by catalyzing the hydrolysis of the phosphodiester bond between the 5′-ribose of a nucleoside and the phosphate group of the 3′-ribose of an adjacent pyrimidine (Cytosine or Uridine).

This enzymatic reaction produces 2′, 3′-cyclic phosphate intermediates, which are further hydrolyzed into 3′-nucleoside phosphates. Because of this specificity, RNase A is the gold standard for removing RNA residues in plasmid extraction and genomic DNA purification.

The Advantage of Recombinant Production (Animal-Free)

Traditionally, RNase A was extracted from bovine pancreases. However, this method presents two significant drawbacks:

• DNase Contamination: Animal-derived RNase A often contains residual DNase, which can inadvertently degrade your target DNA and reduce yields.
• Safety Concerns: Use of animal-derived components poses risks in regulated environments.

Tinzyme’s Recombinant RNase A is produced using a specialized yeast expression system. This ensures:

• Zero DNase Activity: High-purity enzymes that protect your DNA samples.
• Animal-Free Process: No animal-derived components are used at any stage of production, making it ideal for gene therapy and cell therapy applications.

Redefining Stability: 4 Months at Room Temperature

The biggest challenge for kit manufacturers is the thermolability of enzymes. Most molecular enzymes require cold-chain logistics, which increases transportation costs and complexity.

To solve this, Tinzyme has optimized its RNase A Solution (Cat. No. RA02) for maximum stability. Our long-term testing confirms that this recombinant solution remains fully stable and active for over 4 months at:

Room Temperature (25°C)

Elevated Temperatures (37°C)

Why This Matters for Your Business

• Simplified Logistics: No need for dry ice or specialized cold-chain shipping.
• Kit Optimization: Allows for the entire nucleic acid extraction kit to be stored and transported at ambient temperatures.
• Reliability: Guaranteed enzymatic efficiency even if temperature fluctuations occur during transit.

Conclusion

Tinzyme’s Recombinant RNase A Solution combines high-performance purity with industry-leading thermal stability. By eliminating DNase contamination and the need for refrigeration, we provide a robust, cost-effective solution for researchers and kit manufacturers worldwide.

Experience the stability of Tinzyme RNase A today.

1. Freeze/Thaw Cycle Test

This test evaluates the stability of dNTPs when subjected to repeated freezing and thawing, simulating frequent laboratory use.

2. Thermal Stability Test

This test measures the degradation of dNTPs when stored at room temperature (25℃) and elevated temperature (37℃) for 10 days.

3. Long-Term Stability Test

Data represents the purity maintained over a 5-year period under standard storage conditions.

In molecular biology experiments, we perform nucleic acid extraction and purification, which often involves various reagents.

Today, we will focus on Carrier RNA, also known as a nucleic acid coprecipitant.

1. Concept and Classification of Carrier RNA

Carrier RNA, also called Nucleic Acid Coprecipitant, refers to a mixture of RNA fragments ranging from 200 to 3000 nucleotides (nt). Common types include PolyA potassium salt, E. coli total RNA, yeast total RNA, and tRNA.

As an auxiliary substance for nucleic acid precipitation, Carrier RNA comes in several types:

1.1 Glycogen

Glycogen serves as an auxiliary precipitant for nucleic acids and generally performs better than tRNA or sonicated DNA. Since glycogen contains no DNase or RNase, it minimally affects subsequent PCR, RT-PCR, and restriction enzyme reactions. According to literature reports, ligation products precipitated with glycogen show virtually no interference with subsequent bacterial transformation. Glycogen at 0.001 mg/mL does not inhibit TdT (Terminal Deoxynucleotidyl Transferase), concentrations below 2 mg/mL almost never affect reverse transcriptase activity, and 0.02 mg/mL glycogen does not inhibit T4 RNA ligase activity. However, glycogen can interfere with DNA-protein interactions. Typically, 1 μL of 20 mg/mL glycogen solution is sufficient to precipitate picogram-level DNA or RNA from a 1 mL solution system.

1.2 Yeast tRNA Solution

When used at a final concentration of 10–20 µg/mL, yeast tRNA serves as an effective coprecipitant for trace nucleic acid recovery.
Since tRNA is a substrate for polynucleotide kinase and terminal transferase, tRNA cannot be used as a coprecipitant if the recovered DNA or RNA will be used for such reactions. If the recovered RNA is intended for RT-PCR, using tRNA may interfere with the specificity of the reaction.

1.3 Linear Acrylamide (LPA)

Linear Acrylamide, also known as Linear Polyacrylamide (LPA), is a coprecipitant that facilitates nucleic acid precipitation during purification processes. Essentially, acrylamide is a neutral carrier of non-biological origin, thus containing no potential nucleic acid or nuclease contamination. Additionally, it does not interfere with A260/A280 readings and does not inhibit polymerase or restriction endonuclease activities, making it compatible with subsequent molecular biology applications such as PCR and enzymatic digestion. Typically, 2-4 μL (10-20 μg) of 5 mg/mL solution is sufficient for precipitating DNA or RNA from 1 mL of solution.

2. Mechanism of Action

2.1 Reduction of Adsorption Losses: During nucleic acid extraction, electrostatic charges on centrifuge tube walls (typically polypropylene materials) can adsorb nucleic acids, leading to reduced extraction yields. The addition of Carrier RNA eliminates electrostatic effects, ensuring efficient binding of nucleic acids to purification columns and improving elution efficiency.

2.2 Decreased Nuclease Attack Probability: In extraction environments, RNases and other nucleases may degrade trace amounts of RNA. The presence of Carrier RNA reduces wall adsorption of target nucleic acids, thereby decreasing the probability of nuclease attack on the nucleic acids being extracted.

2.3 Enhanced Binding and Elution Efficiency: When RNA concentration is very low, minute amounts of RNA may be insufficient to form a precipitate. The addition of Carrier RNA provides adequate nucleic acid mass to facilitate precipitation formation.

3. Case Study

In plasma extraction, the primary challenge lies in the generally low content and small fragment size of cell-free DNA (cfDNA) in plasma samples.

We performed extraction from 200 μL of plasma, designing experiments with and without Carrier RNA to investigate its effect on the recovery efficiency of small fragment nucleic acid purification. Following the kit protocol, Groups 1 and 2 were supplemented with 5 μL of Carrier RNA, while Groups 3 and 4 received none. After extraction, fluorescent PCR amplification was performed to observe the results.
Analysis of the results shows that the CT values of samples 1 and 2 (with Carrier RNA) were approximately 1.5 cycles lower than sample 3 and about 3.5 cycles lower than sample 4. This indicates that in nucleic acid purification systems without Carrier RNA, the recovery efficiency of trace nucleic acids becomes unstable, ranging from 1/10 to 1/3 of the efficiency achieved in systems containing Carrier RNA.

4. When is Carrier RNA Essential?

We recommend adding Carrier RNA in the following three situations:

4.1 Extremely limited sample volume (e.g., swab wash fluid, trace serum)
4.2 Extremely low target nucleic acid concentration (e.g., early-stage viral infections, ctDNA/circulating tumor DNA)
4.3 When using ethanol precipitation methods (bead-based methods may not require it)

From: Molecular Biology Knowledge Base

As the Chinese New Year (Spring Festival) approaches, we would like to extend our warmest wishes to you and your family. Please be advised that our operations and shipping schedules will be adjusted during this festive period.

📅 Holiday Schedule

Our team will be taking a break to celebrate with their families on the following dates:

Office & Warehouse Holiday: [2026-02-15] – [2026-02-23]

Resume Normal Operations: [2026-02-24]

🚚 Shipping & Delivery Deadlines

Please note that logistics and courier services across China will also be taking a break. To ensure you receive your orders on time, please take note of the following:

Final Order Cut-off: All orders placed after [2026-02-11] will be processed but may not be shipped until we return.

Shipping Suspension: Local and international couriers will begin pausing services approximately 3-5 days before the official holiday starts.

Expect Delays: Any orders placed during the holiday period will be fulfilled chronologically starting from [2026-02-24]. Please expect a slight delay in delivery as we clear the holiday backlog.

❤️ Customer Support

While our shipping department is closed, our customer service team will have limited availability via email. We appreciate your patience and understanding if response times are longer than usual.

We suggest placing your orders as early as possible to avoid the holiday rush. Thank you for your continued support and for being a part of our community!

Wishing you a prosperous and Happy Year of the Horse!

Best Regards,

The Tinzyme Team

Product Code: PK01

We hereby declare that our Proteinase K (Product No. PK01) is manufactured under strict quality control standards and meets the following criteria:

• Animal-Free Composition: The product does not contain any ingredients derived from animal sources, nor does it contain any components contaminated by animal-derived substances.
• TSE/BSE Compliance: This product has not been exposed to animals affected by, or under quarantine for, Transmissible Spongiform Encephalopathy (TSE) or Bovine Spongiform Encephalopathy (BSE).
• Research Use Only: This product is designed exclusively for scientific research and laboratory experiments, specifically for protein degradation.

Disclaimer: This product is not intended for human or veterinary use, nor is it for use in food, cosmetics, or medicinal products. It is strictly for in vitro scientific research purposes.

PCM80
Universal FastStart Probe Mixture（UNG）

PCM31 Comparison of Amplification Effects of Different High Fidelity Mixes – Different Species, Different Models

① Brand A ② Brand B ③ TZ ④ PCM31

Newly designed model primers:
Human primers: H5k, H5k high GC, H10k
Mouse Primer: M5k, M5k, High GC.M10k

Newly designed model primers
Rice Primers: 05k, o5k – High GC, 010k
cDNA Primers: C-2.8k, C-4.5k

PCM80 Anti inhibition Performance Test: Application of Inhibitors (Ethanol, Blood, EGTA) Test Reagent for Anti inhibition Ability

There was no significant difference in CT values when adding 2mMEGTA as the final concentration. However, when adding 0.2% ASFV pig blood or 3% ethanol as the final concentration, the CT values advanced by 1-2 compared to 2xmix. Adding blood signals resulted in varying degrees of reduction (25% -28%).

PCM80 Digestive Ability Test

Application of human genome exploration and 2xmix (UNG) for one round of amplification (20cycles), followed by ten fold gradient dilution of one round of amplification products. The amplification products diluted by 103, 104, 105, 106, and 107 times were selected and amplified using no anti fouling system reaction solution and anti fouling system reaction solution, respectively. The CT differences at the same template concentration were compared.

Comparison of human genome template amplification:

Comparison of amplification of products containing dU in one round:

Conclusion: By amplifying 1ng/uL gDNA, PCM80 can be performed about 2 times earlier than UNG CT without anti fouling system; After amplifying the product containing dU in one round, PCM80 showed a significant CT lag effect compared to UNG without anti fouling system (CT difference greater than 10). When the product was diluted 106 times in one round, PCM80 did not amplify, indicating a direct relationship with the UNG system and strong digestive ability.

There are two common principles and methods for microRNA reverse transcription/microRNA fluorescence quantitative detection:

1. PolyA tail addition method (most commonly used)
2. Stem loop

The first method: PolyA tail addition

To complete the PolyA tail method, it actually requires two components. One is a microRNA reverse transcription kit, and the other is a microRNA fluorescence quantitative detection kit. The biggest feature of the PolyA tail method is that the primers used by each company are confidential and different, so each company’s polyA tail method microRNA reverse transcription kit and matching microRNA fluorescence quantitative detection kit must be used together. If you use Company A’s microRNA reverse transcription kit, you must use Company A’s matching microRNA fluorescence quantitative detection kit. If you use Company A’s microRNA reverse transcription kit but use Company B’s fluorescence quantitative detection kit, the experiment may fail. Of course, there is an exception, which is that when Company A is making a microRNA reverse transcription test kit, it has already provided its own company with special primers for the microRNA fluorescence quantitative detection kit. Therefore, it is not necessary to buy Company A’s microRNA fluorescence quantitative detection kit for use, but to buy any company’s fluorescence quantitative mix and match it with this special primer.

PolyA Tail Method Product Introduction:

PCK50 Enhanced microRNA First Chain Synthesis Kit

PCK51 enhanced microRNA fluorescence quantitative PCR detection kit (consisting of fluorescence quantitative mix and special matching primers)

PCK50+PCK51 must be used together. If you buy PCK50, you will definitely need to buy PCK51 to use it together.

If you want to only buy PCK50 for microRNA reverse transcription and do not want to buy the matching PCK51, downstream fluorescence quantitative detection using other companies’ fluorescence quantitative mix may not be able to complete downstream experiments due to primer mismatch.

PCK52 Enhanced microRNA Reverse Transcription/Fluorescence Quantitative Detection Kit (All In One)

PCK52=PCK50+4 PCK51. Generally speaking, microRNA reverse transcription is used less and microRNA detection is used more. This ratio arrangement is suitable for practical situations. At the same time, it can be made into a two in one kit for users to purchase together, which can be cheaper than purchasing separately.

Second type: Stem loop

Let’s talk about the second principle of microRNA reverse transcription, the stem loop method microRNA reverse transcription. Its biggest feature is that the microRNA reverse transcription kit does not need to be matched with a specific microRNA detection kit. As long as you purchase the stem loop method microRNA reverse transcription kit, it can be used with any company’s ordinary fluorescence quantitative mix.

Product Introduction of Stem Ring Method

PCK53-MRNA Stem Loop cDNA Kit Stem Loop microRNA Reverse Transcription Kit

A common misconception persists in molecular biology labs: relying solely on spectrophotometers (e.g., Nanodrop) to assess nucleic acid purity and quality. While instruments like Nanodrop provide valuable data, their limitations in evaluating broad-spectrum purity often lead to experimental failures. This article clarifies why gel electrophoresis is indispensable for ensuring reliable RNA integrity and purity.

Narrow-Sense vs. Broad-Sense Purity: A Fundamental Distinction

To resolve confusion, we must differentiate two critical concepts:

Narrow-Sense Purity

Refers to the absence of residual proteins (A260/A280 ratio) and salt ions (A260/A230 ratio).

Broad-Sense Purity

Encompasses all factors affecting usability, including:

• Residual DNA contamination
• RNA degradation (fragmented RNA)
• Invisible contaminants (e.g., polysaccharides, polyphenols)

Nanodrop spectrophotometers excel at assessing narrow-sense purity but fail to detect broader issues like DNA carryover, RNA degradation, or non-protein contaminants.

Why Spectrophotometers Fall Short

Blind to DNA Contamination

Genomic DNA absorbs light at 260 nm, inflating RNA concentration readings. For example, a sample with 50% DNA contamination may falsely report double the RNA concentration.

Misses RNA Degradation

Degraded RNA fragments exhibit a hyperchromic effect, artificially elevating OD260 values. Spectrophotometers cannot distinguish intact RNA from fragmented RNA.

Ignores “Invisible” Contaminants

Polysaccharides, polyphenols, or enzymatic inhibitors (common in plant or bone tissues) do not absorb UV light at standard wavelengths, evading detection.

Gel Electrophoresis: The Definitive Quality Check

Gel electrophoresis provides visual validation of nucleic acid integrity and purity:

RNA Integrity

• Sharp 28S/18S ribosomal RNA bands (animal samples) confirm intact RNA.
• Degraded RNA appears as a smear, even if OD ratios are “perfect.”

DNA Contamination

Discrete genomic DNA bands reveal contamination invisible to spectrophotometers.

Quantitative Accuracy

Intact RNA concentrations correlate with band intensity, unlike fragmented RNA with inflated OD values.

Case Study

A lab measured “high-quality” RNA (A260/A280 = 2.0) via Nanodrop, but RT-qPCR failed. Gel electrophoresis revealed severe RNA degradation and DNA contamination—issues entirely missed by spectrophotometry.

Consequences of Skipping Electrophoresis

Using spectrophotometers alone risks:

False High Concentrations

Degraded RNA or contaminants inflate OD260, leading to overestimation of usable RNA.

Downstream Experimental Failures

• Scenario A: Severely degraded RNA → Failed reverse transcription.
• Scenario B: Partially degraded RNA → Inaccurate quantification (e.g., qPCR Ct value shifts).
• Scenario C: DNA contamination → Incorrect RNA concentration adjustments.
• Scenario D: Enzyme inhibitors → Reduced reverse transcription efficiency.

Real-World Example

Plant RNA extracts with polyphenol contamination showed “ideal” OD ratios but completely inhibited downstream reactions. Electrophoresis detected no RNA bands, exposing the flaw in relying solely on spectrophotometers.

A Standardized Workflow for Reliable Results

Dual Verification

• Use spectrophotometers for narrow-sense purity (A260/A280 and A260/A230).
• Validate broad-sense purity via gel electrophoresis.

Critical Thresholds

• Intact RNA: 28S band intensity should be 1.5–2× the 18S band.
• Degraded RNA: Discard samples showing smearing ≥50% of the lane.

Sample-Specific Awareness

Challenging samples (e.g., plant tissues, bone): Prioritize electrophoresis even if OD values appear normal.

Conclusion

In precision-driven research, overlooking gel electrophoresis is a gamble. While spectrophotometers efficiently screen for protein and salt contaminants, only electrophoresis can confirm RNA integrity, detect DNA carryover, and expose invisible inhibitors. Integrate both methods to ensure your nucleic acid prep is truly “pure”—not just on paper, but in practice.

Related Products

• EZ100-100g EZ Agarose Tablets
• ST04-1ml Safe Green Stain
• ST05-1ml Safe Red Stain
• DNK0701 Blood and Tissue DNA Mini Kit
• DNK1001 Genomic Fast DNA Kit
• DNK4501 FastBeat Soil DNA Kit (Bead Beating)

I. Principles and Limitations of Spectrophotometry

Spectrophotometers estimate nucleic acid concentration by measuring absorbance at 260 nm (OD value). This calculation assumes that the solution contains only pure, intact RNA and that OD variations are solely caused by the target RNA. In reality, this ideal scenario is nearly unattainable in practice.

Three Major Interference Sources

Protein Contamination: Residual proteins absorb light at 280 nm, skewing the A260/A280 ratio.

DNA Residue: Genomic DNA also absorbs at 260 nm.

RNA Degradation: Short RNA fragments from degradation exhibit a hyperchromic effect, artificially inflating OD values.

Case Study: A lab reported an RNA concentration of 2000 ng/μL using a spectrophotometer, yet reverse transcription failed. Electrophoresis later revealed complete RNA degradation—the “high concentration” was merely an artifact from fragmented RNA.

II. The Necessity of Dual Verification

For example, in plant secondary metabolic tissues: Normal RNA concentrations range between 50–100 ng/μL. If a kit reports 800 ng/μL, phenolic compound contamination likely causes OD inflation—a phenomenon easily identified by smearing on an electrophoresis gel.

III. The Critical Role of Electrophoresis

Agarose gel electrophoresis provides visual insights into:

• RNA Integrity: Sharpness of 28S/18S bands (animal samples)
• Degradation Level: Smearing patterns
• Impurity Presence: Abnormal band positions

Key Data: Intact RNA shows a 28S band 1.5–2 times brighter than the 18S band. Diffuse smearing—even with a “perfect” A260/A280 ratio of 2.0—indicates unsuitability for full-length transcriptome analysis.

IV. Standardized Detection Protocol

Dual-Method Approach

Combine OD measurements with electrophoresis validation.

Concentration Correction Formula

True Concentration = Nanodrop Reading × (Intact Band Intensity Ratio)

Sample-Specific Awareness

For challenging samples (e.g., neural tissue), 20 ng/μL of intact RNA outperforms 500 ng/μL of degraded RNA.

Real-World Example: A research group at a top-tier university struggled for six months to replicate experiments. After implementing electrophoresis, they discovered their “high-concentration” commercial RNA extracts contained genomic DNA contamination.

Conclusion

In the era of precision medicine, reliable data begins with standardized protocols. Establishing an “OD Screening + Electrophoresis Verification” system not only rescues failing experiments but also embodies scientific rigor. Remember: True technical excellence is rooted in respecting fundamental principles.

Authored by RNA Extraction Technology Experts. We advocate: Every dataset must withstand the strictest validation.

Related products

• EZ100
• LE100
• ST04
• ST05
• RNK0701
• RNK3401
• RNK2302
• RNK0101