---
frameworks:
- PyTorch
language:
- en
license: mit
tags:
- OneScience
- bioscience
- enzyme-optimum-pH-prediction
- protein-language-model
- EpHod
tasks:
- regression
---

<p align="center">
  <strong>
    <span style="font-size: 30px;">EpHod</span>
  </strong>
</p>

# Model Introduction

EpHod is an ensemble model for predicting the catalytic optimum pH (`pHopt`) of enzymes.

The model first uses ESM-1v to encode amino acid sequences into protein representations and then combines predictions from a Residual Lightweight Attention network (RLATtr) and a Support Vector Regression model (SVR).

Paper: [Machine learning prediction of enzyme optimum pH](https://doi.org/10.1038/s42256-025-01026-6)

# Model Description

The EpHod inference pipeline contains three main prediction components:

- **ESM-1v:** Encodes enzyme sequences into 1280-dimensional residue-level protein representations;
- **RLATtr:** Uses a residual lightweight attention network to predict `pHopt` and can optionally output residue-level attention weights and a 2560-dimensional EpHod protein representation;
- **SVR:** Performs support vector regression using pooled and standardized ESM-1v representations;
- **Ensemble:** Uses the average of the RLATtr and SVR predictions as the final `pHopt` prediction.

The official RLATtr model was first pretrained on approximately 1.9 million proteins labeled with optimum environmental pH (`pHenv`) and was then fine-tuned on 9,855 enzymes labeled with catalytic optimum pH (`pHopt`).

Input sequences longer than 1022 residues are truncated.

To avoid pooling-related bias, the current inference entry point uses a fixed batch size of 1.

# Use Cases

| Use Case | Description |
| --- | --- |
| Enzyme optimum pH prediction | Predict catalytic optimum pH from an enzyme amino acid sequence. |
| Enzyme candidate screening | Compare multiple candidate enzyme sequences based on predicted optimum pH. |
| Attention analysis | Optionally save residue-level RLATtr attention weights. |
| Protein representation extraction | Optionally save the final 2560-dimensional RLATtr protein representation. |

# Usage

## 1. OneCode

You can use the OneCode online environment for an intelligent one-click AI4S programming experience:

[Try OneCode for AI4S Programming](https://web-2069360198568017922-iaaj.ksai.scnet.cn:58043/home)

## 2. Manual Installation

### Hardware Requirements

- Supports CPU and accelerator devices supported by PyTorch;
- GPU or SCNet DCU is recommended for ESM-1v inference;
- CPU execution is supported but is significantly slower;
- ESM-1v contains approximately 650 million parameters;
- Device memory usage depends on sequence length. If device memory is insufficient, reduce the input sequence length or process sequences individually.

### Download the Model Package

Install the Hugging Face command-line tool and download the model repository:

```bash

python -m pip install -U huggingface_hub

hf download OneScience-Group/EpHod --local-dir ./EpHod
cd EpHod
```

### Install the Runtime Environment

**DCU Environment**

```bash
# Activate DTK and Conda first
conda create -n onescience311 python=3.11 -y
conda activate onescience311

python -m pip install "onescience[bio-dcu]" \
  -i http://mirrors.onescience.ai:3141/pypi/simple/ \
  --trusted-host mirrors.onescience.ai
```
**GPU Environment**

```bash
# Activate Conda first
conda create -n onescience311 python=3.11 -y
conda activate onescience311

python -m pip install "onescience[bio-gpu]" \
  -i http://mirrors.onescience.ai:3141/pypi/simple/ \
  --trusted-host mirrors.onescience.ai
```

Install the additional dependencies required by EpHod:

```bash
python -m pip install --no-deps -r requirements.txt
```

### Weight Preparation

Inference requires all three of the following assets:

| Asset | Relative Path | Purpose |
| --- | --- | --- |
| ESM-1v 650M weights | `weight/esm1v_t33_650M_UR90S_1.pt` | Generate residue-level protein representations |
| RLATtr weights | `weight/ESM1v-RLATtr.pt` | Neural-network prediction branch |
| SVR model and normalization statistics | `weight/ESM1v-SVR.pkl` | Support Vector Regression prediction branch |

Official sources:

- [ESM-1v main checkpoint](https://dl.fbaipublicfiles.com/fair-esm/models/esm1v_t33_650M_UR90S_1.pt)
- [EpHod RLATtr weights and training data](https://doi.org/10.5281/zenodo.14252615)
- `ESM1v-SVR.pkl` is distributed with the official EpHod repository.

### Quick Inference

The following command uses a validated smoke-test sequence:

```bash
python scripts/inference.py \
  --fasta_path conf/data/smoke.fasta \
  --output_path output/smoke/prediction.csv \
  --verbose 1 \
  --save_attention_weights 0 \
  --save_embeddings 0
```

A complete example using the provided test sequences:

```bash
python scripts/inference.py \
  --fasta_path conf/data/test_sequences.fasta \
  --output_path output/inference/prediction.csv \
  --verbose 1 \
  --save_attention_weights 0 \
  --save_embeddings 0
```

The output CSV contains three prediction columns:

```text
RLATtr,SVR,Ensemble
```

Their meanings are:

- `RLATtr`: optimum-pH prediction from the neural-network branch;
- `SVR`: optimum-pH prediction from the support vector regression branch;
- `Ensemble`: arithmetic mean of the RLATtr and SVR predictions and the recommended final EpHod prediction.

The `--output_path` argument directly specifies the complete output CSV path and automatically creates its parent directory when required.

The original `--save_dir` and `--csv_name` options remain available.

If `--output_path` is not specified, the output path is generated from `--save_dir` and `--csv_name`.

### Save Attention Weights and Protein Representations

Set the corresponding options to `1`:

```bash
python scripts/inference.py \
  --fasta_path conf/data/smoke.fasta \
  --output_path output/features/prediction.csv \
  --save_attention_weights 1 \
  --save_embeddings 1
```

The output includes:

```text
output/features/
├── attention_weights/
├── embeddings.csv
└── prediction.csv
```

`attention_weights/` stores residue-level RLATtr attention information.

`embeddings.csv` stores the extracted EpHod protein representations.

`prediction.csv` stores the RLATtr, SVR, and ensemble optimum-pH predictions.

# OneScience Official Resources

| Platform | OneScience Main Repository | Skills Repository |
| --- | --- | --- |
| Gitee | https://gitee.com/onescience-ai/onescience | https://gitee.com/onescience-ai/oneskills |
| GitHub | https://github.com/onescience-ai/OneScience | https://github.com/onescience-ai/oneskills |

# Citation and License

- EpHod paper: [Machine learning prediction of enzyme optimum pH](https://doi.org/10.1038/s42256-025-01026-6)
- Official implementation: https://github.com/jafetgado/EpHod
- EpHod model and data: [Machine learning prediction of enzyme optimal pH](https://doi.org/10.5281/zenodo.14252615)
- The upstream EpHod implementation is distributed under the MIT License.
- This model package provides SCNet/DCU runtime adaptation and directory organization based on the official implementation.
- The adaptation does not modify the copyright status, licenses, or terms of use of the original paper, source code, model weights, datasets, ESM-1v assets, or other third-party resources.